eruda/doc/UTIL_API.md

Eruda Util Documentation

$

jQuery like style dom manipulator.

Available methods

offset, hide, show, first, last, get, eq, on, off, html, text, val, css, attr, data, rmAttr, remove, addClass, rmClass, toggleClass, hasClass, append, prepend, before, after

const $btn = $('#btn');
$btn.html('eustia');
$btn.addClass('btn');
$btn.show();
$btn.on('click', function () {
    // Do something...
});

$attr

Element attribute manipulation.

Get the value of an attribute for the first element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Attribute name
return	string	Attribute value of first element

Set one or more attributes for the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Attribute name
value	string	Attribute value

Name	Type	Desc
element	string array element	Elements to manipulate
attributes	object	Object of attribute-value pairs to set

remove

Remove an attribute from each element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Attribute name

$attr('#test', 'attr1', 'test');
$attr('#test', 'attr1'); // -> test
$attr.remove('#test', 'attr1');
$attr('#test', {
    'attr1': 'test',
    'attr2': 'test'
});

$class

Element class manipulations.

add

Add the specified class(es) to each element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
names	string array	Classes to add

has

Determine whether any of the matched elements are assigned the given class.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Class name
return	boolean	True if elements has given class name

toggle

Add or remove one or more classes from each element in the set of matched elements, depending on either the class's presence or the value of the state argument.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Class name to toggle

remove

Remove a single class, multiple classes, or all classes from each element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Class names to remove

$class.add('#test', 'class1');
$class.add('#test', ['class1', 'class2']);
$class.has('#test', 'class1'); // -> true
$class.remove('#test', 'class1');
$class.has('#test', 'class1'); // -> false
$class.toggle('#test', 'class1');
$class.has('#test', 'class1'); // -> true

$css

Element css manipulation.

Get the computed style properties for the first element in the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Property name
return	string	Css value of first element

Set one or more CSS properties for the set of matched elements.

Name	Type	Desc
element	string array element	Elements to manipulate
name	string	Property name
value	string	Css value

Name	Type	Desc
element	string array element	Elements to manipulate
properties	object	Object of css-value pairs to set

$css('#test', {
    color: '#fff',
    background: 'black'
});
$css('#test', 'display', 'block');
$css('#test', 'color'); // -> #fff

$data

Wrapper of $attr, adds data- prefix to keys.

$data('#test', 'attr1', 'eustia');

$event

bind events to certain dom elements.

function clickHandler() {
    // Do something...
}
$event.on('#test', 'click', clickHandler);
$event.off('#test', 'click', clickHandler);

$insert

Insert html on different position.

before

Insert content before elements.

after

Insert content after elements.

prepend

Insert content to the beginning of elements.

append

Insert content to the end of elements.

Name	Type	Desc
element	string array element	Elements to manipulate
content	string	Html strings

// <div id="test"><div class="mark"></div></div>
$insert.before('#test', '<div>licia</div>');
// -> <div>licia</div><div id="test"><div class="mark"></div></div>
$insert.after('#test', '<div>licia</div>');
// -> <div id="test"><div class="mark"></div></div><div>licia</div>
$insert.prepend('#test', '<div>licia</div>');
// -> <div id="test"><div>licia</div><div class="mark"></div></div>
$insert.append('#test', '<div>licia</div>');
// -> <div id="test"><div class="mark"></div><div>licia</div></div>

$offset

Get the position of the element in document.

Name	Type	Desc
element	string array element	Elements to get offset

$offset('#test'); // -> {left: 0, top: 0, width: 0, height: 0}

$property

Element property html, text, val getter and setter.

html

Get the HTML contents of the first element in the set of matched elements or set the HTML contents of every matched element.

text

Get the combined text contents of each element in the set of matched elements, including their descendants, or set the text contents of the matched elements.

val

Get the current value of the first element in the set of matched elements or set the value of every matched element.

$property.html('#test', 'licia');
$property.html('#test'); // -> licia

$remove

Remove the set of matched elements from the DOM.

Name	Type	Desc
element	string array element	Elements to delete

$remove('#test');

$safeEls

Convert value into an array, if it's a string, do querySelector.

Name	Type	Desc
value	element array string	Value to convert
return	array	Array of elements

$safeEls(document.querySelector('.test'));
$safeEls(document.querySelectorAll('.test'));
$safeEls('.test'); // -> Array of elements with test class

$show

Show elements.

Name	Type	Desc
element	string array element	Elements to show

$show('#test');

Class

Create JavaScript class.

Name	Type	Desc
methods	object	Public methods
[statics]	object	Static methods
return	function	Function used to create instances

const People = Class({
    initialize: function People(name, age) {
        this.name = name;
        this.age = age;
    },
    introduce: function () {
        return 'I am ' + this.name + ', ' + this.age + ' years old.';
    }
});

const Student = People.extend({
    initialize: function Student(name, age, school) {
        this.callSuper(People, 'initialize', arguments);

        this.school = school;
    },
    introduce: function () {
        return this.callSuper(People, 'introduce') + '\n I study at ' + this.school + '.';
    }
}, {
    is: function (obj) {
        return obj instanceof Student;
    }
});

const a = new Student('allen', 17, 'Hogwarts');
a.introduce(); // -> 'I am allen, 17 years old. \n I study at Hogwarts.'
Student.is(a); // -> true

Emitter

Event emitter class which provides observer pattern.

on

Bind event.

off

Unbind event.

once

Bind event that trigger once.

Name	Type	Desc
event	string	Event name
listener	function	Event listener

emit

Emit event.

Name	Type	Desc
event	string	Event name
...args	*	Arguments passed to listener

mixin

[static] Mixin object class methods.

Name	Type	Desc
obj	object	Object to mixin

const event = new Emitter();
event.on('test', function () { console.log('test') });
event.emit('test'); // Logs out 'test'.
Emitter.mixin({});

Enum

Enum type implementation.

constructor

Name	Type	Desc
arr	array	Array of strings

Name	Type	Desc
obj	object	Pairs of key and value

const importance = new Enum([
    'NONE', 'TRIVIAL', 'REGULAR', 'IMPORTANT', 'CRITICAL'
]);
const val = 1;
if (val === importance.CRITICAL) {
    // Do something.
}

LocalStore

LocalStorage wrapper.

Extend from Store.

constructor

Name	Type	Desc
name	string	LocalStorage item name
data	object	Default data

const store = new LocalStore('licia');
store.set('name', 'licia');

Logger

Simple logger with level filter.

constructor

Name	Type	Desc
name	string	Logger name
level=DEBUG	number	Logger level

setLevel

Set level.

Name	Type	Desc
level	number string	Logger level

getLevel

Get current level.

trace, debug, info, warn, error

Logging methods.

Log Levels

TRACE, DEBUG, INFO, WARN, ERROR and SILENT.

const logger = new Logger('licia', Logger.level.ERROR);
logger.trace('test');

// Format output.
logger.formatter = function (type, argList) {
    argList.push(new Date().getTime());

    return argList;
};

logger.on('all', function (type, argList) {
    // It's not affected by log level.
});

logger.on('debug', function (argList) {
    // Affected by log level.
});

MutationObserver

Safe MutationObserver, does nothing if MutationObserver is not supported.

const observer = new MutationObserver(function (mutations) {
    // Do something.
});
observer.observe(document.documentElement);
observer.disconnect();

Select

Simple wrapper of querySelectorAll to make dom selection easier.

constructor

Name	Type	Desc
selector	string	Dom selector string

find

Get desdendants of current matched elements.

Name	Type	Desc
selector	string	Dom selector string

each

Iterate over matched elements.

Name	Type	Desc
fn	function	Function to execute for each element

const $test = new Select('#test');
$test.find('.test').each(function (idx, element) {
    // Manipulate dom nodes
});

Stack

Stack data structure.

clear

Clear the stack.

push

Add an item to the stack.

Name	Type	Desc
item	*	Item to add
return	number	Current size

pop

Get the last item of the stack.

peek

Get the last item without removing it.

forEach

Iterate over the stack.

Name	Type	Desc
iterator	function	Function invoked iteration
[ctx]	*	Function context

toArr

Convert the stack to a JavaScript array.

const stack = new Stack();

stack.push(2); // -> 1
stack.push(3); // -> 2
stack.pop(); // -> 3

Store

Memory storage.

Extend from Emitter.

constructor

Name	Type	Desc
data	object	Initial data

set

Set value.

Name	Type	Desc
key	string	Value key
val	*	Value to set

Set values.

Name	Type	Desc
vals	object	Key value pairs

This emit a change event whenever is called.

get

Get value.

Name	Type	Desc
key	string	Value key
return	*	Value of given key

Get values.

Name	Type	Desc
keys	array	Array of keys
return	object	Key value pairs

remove

Remove value.

Name	Type	Desc
key	string array	Key to remove

clear

Clear all data.

each

Iterate over values.

Name	Type	Desc
fn	function	Function invoked per interation

const store = new Store('test');
store.set('user', {name: 'licia'});
store.get('user').name; // -> 'licia'
store.clear();
store.each(function (val, key) {
    // Do something.
});
store.on('change', function (key, newVal, oldVal) {
    // It triggers whenever set is called.
});

Url

Simple url manipulator.

constructor

Name	Type	Desc
url=location	string	Url string

setQuery

Set query value.

Name	Type	Desc
name	string	Query name
value	string	Query value
return	Url	this

Name	Type	Desc
query	object	query object
return	Url	this

rmQuery

Remove query value.

Name	Type	Desc
name	string array	Query name
return	Url	this

parse

[static] Parse url into an object.

Name	Type	Desc
url	string	Url string
return	object	Url object

stringify

[static] Stringify url object into a string.

Name	Type	Desc
url	object	Url object
return	string	Url string

An url object contains the following properties:

Name	Desc
protocol	The protocol scheme of the URL (e.g. http:)
slashes	A boolean which indicates whether the protocol is followed by two forward slashes (//)
auth	Authentication information portion (e.g. username:password)
hostname	Host name without port number
port	Optional port number
pathname	URL path
query	Parsed object containing query string
hash	The "fragment" portion of the URL including the pound-sign (#)

const url = new Url('http://example.com:8080?eruda=true');
console.log(url.port); // -> '8080'
url.query.foo = 'bar';
url.rmQuery('eruda');
url.toString(); // -> 'http://example.com:8080/?foo=bar'

ajax

Perform an asynchronous HTTP request.

Name	Type	Desc
options	object	Ajax options

Available options:

Name	Type	Desc
type=get	type	Request type
url	string	Request url
data	string object	Request data
dataType=json	string	Response type(json, xml)
contentType=application/x-www-form-urlencoded	string	Request header Content-Type
success	function	Success callback
error	function	Error callback
complete	function	Callback after request
timeout	number	Request timeout

get

Shortcut for type = GET;

post

Shortcut for type = POST;

Name	Type	Desc
url	string	Request url
[data]	string object	Request data
success	function	Success callback
dataType	function	Response type

ajax({
    url: 'http://example.com',
    data: {test: 'true'},
    error() {},
    success(data) {
        // ...
    },
    dataType: 'json'
});

ajax.get('http://example.com', {}, function (data) {
    // ...
});

allKeys

Retrieve all the names of object's own and inherited properties.

Name	Type	Desc
obj	object	Object to query
[options]	object	Options
return	array	Array of all property names

Available options:

Name	Type	Desc
prototype=true	boolean	Include prototype keys
unenumerable=false	boolean	Include unenumerable keys
symbol=false	boolean	Include symbol keys

Members of Object's prototype won't be retrieved.

const obj = Object.create({zero: 0});
obj.one = 1;
allKeys(obj) // -> ['zero', 'one']

before

Create a function that invokes less than n times.

Name	Type	Desc
n	number	Number of calls at which fn is no longer invoked
fn	function	Function to restrict
return	function	New restricted function

Subsequent calls to the created function return the result of the last fn invocation.

const fn = before(5, function() {});
fn(); // Allow function to be call 4 times at last.

camelCase

Convert string to "camelCase".

Name	Type	Desc
str	string	String to convert
return	string	Camel cased string

camelCase('foo-bar'); // -> fooBar
camelCase('foo bar'); // -> fooBar
camelCase('foo_bar'); // -> fooBar
camelCase('foo.bar'); // -> fooBar

castPath

Cast value into a property path array.

Name	Type	Desc
path	string array	Value to inspect
[obj]	object	Object to query
return	array	Property path array

castPath('a.b.c'); // -> ['a', 'b', 'c']
castPath(['a']); // -> ['a']
castPath('a[0].b'); // -> ['a', '0', 'b']
castPath('a.b.c', {'a.b.c': true}); // -> ['a.b.c']

chunk

Split array into groups the length of given size.

Name	Type	Desc
arr	array	Array to process
size=1	number	Length of each chunk
return	array	Chunks of given size

chunk([1, 2, 3, 4], 2); // -> [[1, 2], [3, 4]]
chunk([1, 2, 3, 4], 3); // -> [[1, 2, 3], [4]]
chunk([1, 2, 3, 4]); // -> [[1], [2], [3], [4]]

clamp

Clamp number within the inclusive lower and upper bounds.

Name	Type	Desc
n	number	Number to clamp
[lower]	number	Lower bound
upper	number	Upper bound
return	number	Clamped number

clamp(-10, -5, 5); // -> -5
clamp(10, -5, 5); // -> 5
clamp(2, -5, 5); // -> 2
clamp(10, 5); // -> 5
clamp(2, 5); // -> 2

clone

Create a shallow-copied clone of the provided plain object.

Any nested objects or arrays will be copied by reference, not duplicated.

Name	Type	Desc
val	*	Value to clone
return	*	Cloned value

clone({name: 'eustia'}); // -> {name: 'eustia'}

cloneDeep

Recursively clone value.

Name	Type	Desc
val	*	Value to clone
return	*	Deep cloned Value

const obj = [{a: 1}, {a: 2}];
const obj2 = cloneDeep(obj);
console.log(obj[0] === obj2[1]); // -> false

concat

Concat multiple arrays into a single array.

Name	Type	Desc
...arr	array	Arrays to concat
return	array	Concatenated array

concat([1, 2], [3], [4, 5]); // -> [1, 2, 3, 4, 5]

contain

Check if the value is present in the list.

Name	Type	Desc
target	array object string	Target object
value	*	Value to check
return	boolean	True if value is present in the list

contain([1, 2, 3], 1); // -> true
contain({a: 1, b: 2}, 1); // -> true
contain('abc', 'a'); // -> true

cookie

Simple api for handling browser cookies.

get

Get cookie value.

Name	Type	Desc
key	string	Cookie key
return	string	Corresponding cookie value

set

Set cookie value.

Name	Type	Desc
key	string	Cookie key
val	string	Cookie value
[options]	object	Cookie options
return	exports	Module cookie

remove

Remove cookie value.

Name	Type	Desc
key	string	Cookie key
[options]	object	Cookie options
return	exports	Module cookie

cookie.set('a', '1', {path: '/'});
cookie.get('a'); // -> '1'
cookie.remove('a');

createAssigner

Used to create extend, extendOwn and defaults.

Name	Type	Desc
keysFn	function	Function to get object keys
defaults	boolean	No override when set to true
return	function	Result function, extend...

dateFormat

Simple but extremely useful date format function.

Name	Type	Desc
date=new Date	Date	Date object to format
mask	string	Format mask
utc=false	boolean	UTC or not
gmt=false	boolean	GMT or not

Mask	Description
d	Day of the month as digits; no leading zero for single-digit days
dd	Day of the month as digits; leading zero for single-digit days
ddd	Day of the week as a three-letter abbreviation
dddd	Day of the week as its full name
m	Month as digits; no leading zero for single-digit months
mm	Month as digits; leading zero for single-digit months
mmm	Month as a three-letter abbreviation
mmmm	Month as its full name
yy	Year as last two digits; leading zero for years less than 10
yyyy	Year represented by four digits
h	Hours; no leading zero for single-digit hours (12-hour clock)
hh	Hours; leading zero for single-digit hours (12-hour clock)
H	Hours; no leading zero for single-digit hours (24-hour clock)
HH	Hours; leading zero for single-digit hours (24-hour clock)
M	Minutes; no leading zero for single-digit minutes
MM	Minutes; leading zero for single-digit minutes
s	Seconds; no leading zero for single-digit seconds
ss	Seconds; leading zero for single-digit seconds
l L	Milliseconds. l gives 3 digits. L gives 2 digits
t	Lowercase, single-character time marker string: a or p
tt	Lowercase, two-character time marker string: am or pm
T	Uppercase, single-character time marker string: A or P
TT	Uppercase, two-character time marker string: AM or PM
Z	US timezone abbreviation, e.g. EST or MDT
o	GMT/UTC timezone offset, e.g. -0500 or +0230
S	The date's ordinal suffix (st, nd, rd, or th)
UTC:	Must be the first four characters of the mask

dateFormat('isoDate'); // -> 2016-11-19
dateFormat('yyyy-mm-dd HH:MM:ss'); // -> 2016-11-19 19:00:04
dateFormat(new Date(), 'yyyy-mm-dd'); // -> 2016-11-19

decodeUriComponent

Better decodeURIComponent that does not throw if input is invalid.

Name	Type	Desc
str	string	String to decode
return	string	Decoded string

decodeUriComponent('%%25%'); // -> '%%%'
decodeUriComponent('%E0%A4%A'); // -> '\xE0\xA4%A'

defaults

Fill in undefined properties in object with the first value present in the following list of defaults objects.

Name	Type	Desc
obj	object	Destination object
*src	object	Sources objects
return	object	Destination object

defaults({name: 'RedHood'}, {name: 'Unknown', age: 24}); // -> {name: 'RedHood', age: 24}

delegate

Event delegation.

add

Add event delegation.

Name	Type	Desc
el	element	Parent element
type	string	Event type
selector	string	Match selector
cb	function	Event callback

remove

Remove event delegation.

const container = document.getElementById('container');
function clickHandler() {
    // Do something...
}
delegate.add(container, 'click', '.children', clickHandler);
delegate.remove(container, 'click', '.children', clickHandler);

detectBrowser

Detect browser info using ua.

Name	Type	Desc
ua=navigator.userAgent	string	Browser userAgent
return	object	Object containing name and version

Browsers supported: ie, chrome, edge, firefox, opera, safari, ios(mobile safari), android(android browser)

const browser = detectBrowser();
if (browser.name === 'ie' && browser.version < 9) {
    // Do something about old IE...
}

detectMocha

Detect if mocha is running.

detectMocha(); // -> True if mocha is running.

detectOs

Detect operating system using ua.

Name	Type	Desc
ua=navigator.userAgent	string	Browser userAgent
return	string	Operating system name

Supported os: windows, os x, linux, ios, android, windows phone

if (detectOs() === 'ios') {
    // Do something about ios...
}

difference

Create an array of unique array values not included in the other given array.

Name	Type	Desc
arr	array	Array to inspect
[...rest]	array	Values to exclude
return	array	New array of filtered values

difference([3, 2, 1], [4, 2]); // -> [3, 1]

each

Iterate over elements of collection and invokes iterator for each element.

Name	Type	Desc
obj	object array	Collection to iterate over
iterator	function	Function invoked per iteration
[ctx]	*	Function context

each({'a': 1, 'b': 2}, function (val, key) {});

endWith

Check if string ends with the given target string.

Name	Type	Desc
str	string	The string to search
suffix	string	String suffix
return	boolean	True if string ends with target

endWith('ab', 'b'); // -> true

escape

Escapes a string for insertion into HTML, replacing &, <, >, ", `, and ' characters.

Name	Type	Desc
str	string	String to escape
return	string	Escaped string

escape('You & Me'); // -> 'You & Me'

escapeJsStr

Escape string to be a valid JavaScript string literal between quotes.

http://www.ecma-international.org/ecma-262/5.1/#sec-7.8.4

Name	Type	Desc
str	string	String to escape
return	string	Escaped string

escapeJsStr('\"\n'); // -> '\\"\\\\n'

escapeJsonStr

Escape json string.

escapeRegExp

Escape special chars to be used as literals in RegExp constructors.

Name	Type	Desc
str	string	String to escape
return	string	Escaped string

escapeRegExp('[licia]'); // -> '\\[licia\\]'

evalCss

Eval css.

extend

Copy all of the properties in the source objects over to the destination object.

Name	Type	Desc
destination	object	Destination object
...sources	object	Sources objects
return	object	Destination object

extend({name: 'RedHood'}, {age: 24}); // -> {name: 'RedHood', age: 24}

extendOwn

Like extend, but only copies own properties over to the destination object.

Name	Type	Desc
destination	object	Destination object
...sources	object	Sources objects
return	object	Destination object

extendOwn({name: 'RedHood'}, {age: 24}); // -> {name: 'RedHood', age: 24}

fileSize

Turn bytes into human readable file size.

Name	Type	Desc
bytes	number	File bytes
return	string	Readable file size

fileSize(5); // -> '5'
fileSize(1500); // -> '1.46K'
fileSize(1500000); // -> '1.43M'
fileSize(1500000000); // -> '1.4G'
fileSize(1500000000000); // -> '1.36T'

filter

Iterates over elements of collection, returning an array of all the values that pass a truth test.

Name	Type	Desc
obj	array	Collection to iterate over
predicate	function	Function invoked per iteration
[ctx]	*	Predicate context
return	array	Array of all values that pass predicate

filter([1, 2, 3, 4, 5], function (val) {
    return val % 2 === 0;
}); // -> [2, 4]

flatten

Recursively flatten an array.

Name	Type	Desc
arr	array	Array to flatten
return	array	New flattened array

flatten(['a', ['b', ['c']], 'd', ['e']]); // -> ['a', 'b', 'c', 'd', 'e']

freeze

Shortcut for Object.freeze.

Use Object.defineProperties if Object.freeze is not supported.

Name	Type	Desc
obj	object	Object to freeze
return	object	Object passed in

const a = {b: 1};
freeze(a);
a.b = 2;
console.log(a); // -> {b: 1}

fullUrl

Add origin to url if needed.

getFileName

Extract file name from url.

getObjType

Get object type.

getProto

Get prototype of an object.

Name	Type	Desc
obj	*	Target object
return	*	Prototype of given object, null if not exists

const a = {};
getProto(Object.create(a)); // -> a

has

Checks if key is a direct property.

Name	Type	Desc
obj	object	Object to query
key	string	Path to check
return	boolean	True if key is a direct property

has({one: 1}, 'one'); // -> true

highlight

Highlight code.

Name	Type	Desc
str	string	Code string
lang=js	string	Language, js, html or css
[style]	object	Keyword highlight style
return	string	Highlighted html code string

Available styles:

comment, string, number, keyword, operator

highlight('const a = 5;', 'js', {
    keyword: 'color:#569cd6;'
}); // -> '<span style="color:#569cd6;">const</span> a <span style="color:#994500;">=</span> <span style="color:#0086b3;">5</span>;'

identity

Return the first argument given.

Name	Type	Desc
val	*	Any value
return	*	Given value

identity('a'); // -> 'a'

idxOf

Get the index at which the first occurrence of value.

Name	Type	Desc
arr	array	Array to search
val	*	Value to search for
fromIdx=0	number	Index to search from
return	number	Value index

idxOf([1, 2, 1, 2], 2, 2); // -> 3

inherits

Inherit the prototype methods from one constructor into another.

Name	Type	Desc
Class	function	Child Class
SuperClass	function	Super Class

function People(name) {
    this._name = name;
}
People.prototype = {
    getName: function () {
        return this._name;
    }
};
function Student(name) {
    this._name = name;
}
inherits(Student, People);
const s = new Student('RedHood');
s.getName(); // -> 'RedHood'

isArgs

Check if value is classified as an arguments object.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an arguments object

(function () {
    isArgs(arguments); // -> true
})();

isArr

Check if value is an Array object.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an Array object

isArr([]); // -> true
isArr({}); // -> false

isArrLike

Check if value is array-like.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is array like

Function returns false.

isArrLike('test'); // -> true
isArrLike(document.body.children); // -> true;
isArrLike([1, 2, 3]); // -> true

isBool

Check if value is a boolean primitive.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a boolean

isBool(true); // -> true
isBool(false); // -> true
isBool(1); // -> false

isBrowser

Check if running in a browser.

console.log(isBrowser); // -> true if running in a browser

isCrossOrig

Check if a url is cross origin.

isDate

Check if value is classified as a Date object.

Name	Type	Desc
val	*	value to check
return	boolean	True if value is a Date object

isDate(new Date()); // -> true

isEl

Check if value is a DOM element.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a DOM element

isEl(document.body); // -> true

isEmpty

Check if value is an empty object or array.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is empty

isEmpty([]); // -> true
isEmpty({}); // -> true
isEmpty(''); // -> true

isErr

Check if value is an error.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an error

isErr(new Error()); // -> true

isErudaEl

See if an element is within eruda.

isFn

Check if value is a function.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a function

Generator function is also classified as true.

isFn(function() {}); // -> true
isFn(function*() {}); // -> true
isFn(async function() {}); // -> true

isMatch

Check if keys and values in src are contained in obj.

Name	Type	Desc
obj	object	Object to inspect
src	object	Object of property values to match
return	boolean	True if object is match

isMatch({a: 1, b: 2}, {a: 1}); // -> true

isMiniProgram

Check if running in wechat mini program.

console.log(isMiniProgram); // -> true if running in mini program.

isMobile

Check whether client is using a mobile browser using ua.

Name	Type	Desc
ua=navigator.userAgent	string	User agent
return	boolean	True if ua belongs to mobile browsers

isMobile(navigator.userAgent);

isNaN

Check if value is an NaN.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an NaN

Undefined is not an NaN, different from global isNaN function.

isNaN(0); // -> false
isNaN(NaN); // -> true

isNative

Check if value is a native function.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a native function

isNative(function () {}); // -> false
isNative(Math.min); // -> true

isNil

Check if value is null or undefined, the same as value == null.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is null or undefined

isNil(null); // -> true
isNil(void 0); // -> true
isNil(undefined); // -> true
isNil(false); // -> false
isNil(0); // -> false
isNil([]); // -> false

isNull

Check if value is an Null.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an Null

isNull(null); // -> true

isNum

Check if value is classified as a Number primitive or object.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is correctly classified

isNum(5); // -> true
isNum(5.1); // -> true
isNum({}); // -> false

isObj

Check if value is the language type of Object.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is an object

Language Spec

isObj({}); // -> true
isObj([]); // -> true

isPrimitive

Check if value is string, number, boolean or null.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a primitive

isPrimitive(5); // -> true
isPrimitive('abc'); // -> true
isPrimitive(false); // -> true

isPromise

Check if value looks like a promise.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value looks like a promise

isPromise(new Promise(function () {})); // -> true
isPromise({}); // -> false

isRegExp

Check if value is a regular expression.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a regular expression

isRegExp(/a/); // -> true

isStr

Check if value is a string primitive.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is a string primitive

isStr('licia'); // -> true

isUndef

Check if value is undefined.

Name	Type	Desc
val	*	Value to check
return	boolean	True if value is undefined

isUndef(void 0); // -> true
isUndef(null); // -> false

kebabCase

Convert string to "kebabCase".

Name	Type	Desc
str	string	String to convert
return	string	Kebab cased string

kebabCase('fooBar'); // -> foo-bar
kebabCase('foo bar'); // -> foo-bar
kebabCase('foo_bar'); // -> foo-bar
kebabCase('foo.bar'); // -> foo-bar

keys

Create an array of the own enumerable property names of object.

Name	Type	Desc
obj	object	Object to query
return	array	Array of property names

keys({a: 1}); // -> ['a']

last

Get the last element of array.

Name	Type	Desc
arr	array	The array to query
return	*	The last element of array

last([1, 2]); // -> 2

loadJs

Inject script tag into page with given src value.

Name	Type	Desc
src	string	Script source
cb	function	Onload callback

loadJs('main.js', function (isLoaded) {
    // Do something...
});

lowerCase

Convert string to lower case.

Name	Type	Desc
str	string	String to convert
return	string	Lower cased string

lowerCase('TEST'); // -> 'test'

lpad

Pad string on the left side if it's shorter than length.

Name	Type	Desc
str	string	String to pad
len	number	Padding length
[chars]	string	String used as padding
return	string	Result string

lpad('a', 5); // -> '    a'
lpad('a', 5, '-'); // -> '----a'
lpad('abc', 3, '-'); // -> 'abc'
lpad('abc', 5, 'ab'); // -> 'ababc'

ltrim

Remove chars or white-spaces from beginning of string.

Name	Type	Desc
str	string	String to trim
[chars]	string array	Characters to trim
return	string	Trimmed string

ltrim(' abc  '); // -> 'abc  '
ltrim('_abc_', '_'); // -> 'abc_'
ltrim('_abc_', ['a', '_']); // -> 'bc_'

map

Create an array of values by running each element in collection through iteratee.

Name	Type	Desc
object	array object	Collection to iterate over
iterator	function	Function invoked per iteration
[context]	*	Function context
return	array	New mapped array

map([4, 8], function (n) { return n * n; }); // -> [16, 64]

mapObj

Map for objects.

Name	Type	Desc
object	object	Object to iterate over
iterator	function	Function invoked per iteration
[context]	*	Function context
return	object	New mapped object

mapObj({a: 1, b: 2}, function (val, key) { return val + 1 }); // -> {a: 2, b: 3}

matcher

Return a predicate function that checks if attrs are contained in an object.

Name	Type	Desc
attrs	object	Object of property values to match
return	function	New predicate function

const filter = require('licia/filter');

const objects = [
    {a: 1, b: 2, c: 3 },
    {a: 4, b: 5, c: 6 }
];
filter(objects, matcher({a: 4, c: 6 })); // -> [{a: 4, b: 5, c: 6}]

memStorage

Memory-backed implementation of the Web Storage API.

A replacement for environments where localStorage or sessionStorage is not available.

const localStorage = window.localStorage || memStorage;
localStorage.setItem('test', 'licia');

memoize

Memoize a given function by caching the computed result.

Name	Type	Desc
fn	function	Function to have its output memoized
[hashFn]	function	Function to create cache key
return	function	New memoized function

const fibonacci = memoize(function(n) {
    return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
});

meta

Document meta manipulation, turn name and content into key value pairs.

Get meta content with given name. If name is omitted, all pairs will be return.

Name	Type	Desc
[name]	string array	Meta name
return	string	Meta content

Set meta content.

Name	Type	Desc
name	string	Meta name
content	string	Meta content

Name	Type	Desc
metas	object	Object of name content pairs

remove

Remove metas.

Name	Type	Desc
name	string array	Meta name

// <meta name="a" content="1"/> <meta name="b" content="2"/> <meta name="c" content="3"/>
meta(); // -> {a: '1', b: '2', c: '3'}
meta('a'); // -> '1'
meta(['a', 'c']); // -> {a: '1', c: '3'}
meta('d', '4');
meta({
    d: '5',
    e: '6',
    f: '7'
});
meta.remove('d');
meta.remove(['e', 'f']);

ms

Convert time string formats to milliseconds.

Turn time string into milliseconds.

Name	Type	Desc
str	string	String format
return	number	Milliseconds

Turn milliseconds into time string.

Name	Type	Desc
num	number	Milliseconds
return	string	String format

ms('1s'); // -> 1000
ms('1m'); // -> 60000
ms('1.5h'); // -> 5400000
ms('1d'); // -> 86400000
ms('1y'); // -> 31557600000
ms('1000'); // -> 1000
ms(1500); // -> '1.5s'
ms(60000); // -> '1m'

nextTick

Next tick for both node and browser.

Name	Type	Desc
cb	function	Function to call

Use process.nextTick if available.

Otherwise setImmediate or setTimeout is used as fallback.

nextTick(function () {
    // Do something...
});

noop

A no-operation function.

noop(); // Does nothing

now

Gets the number of milliseconds that have elapsed since the Unix epoch.

now(); // -> 1468826678701

objToStr

Alias of Object.prototype.toString.

Name	Type	Desc
val	*	Source value
return	string	String representation of given value

objToStr(5); // -> '[object Number]'

once

Create a function that invokes once.

Name	Type	Desc
fn	function	Function to restrict
return	function	New restricted function

function init() {};
const initOnce = once(init);
initOnce();
initOnce(); // -> init is invoked once

optimizeCb

Used for function context binding.

orientation

Screen orientation helper.

on

Bind change event.

off

Unbind change event.

get

Get current orientation(landscape or portrait).

orientation.on('change', function (direction) {
    console.log(direction); // -> 'portrait'
});
orientation.get(); // -> 'landscape'

partial

Partially apply a function by filling in given arguments.

Name	Type	Desc
fn	function	Function to partially apply arguments to
...partials	*	Arguments to be partially applied
return	function	New partially applied function

const sub5 = partial(function (a, b) { return b - a }, 5);
sub5(20); // -> 15

perfNow

High resolution time up to microsecond precision.

const start = perfNow();

// Do something.

console.log(perfNow() - start);

prefix

Add vendor prefixes to a CSS attribute.

Name	Type	Desc
name	string	Property name
return	string	Prefixed property name

dash

Create a dasherize version.

prefix('text-emphasis'); // -> 'WebkitTextEmphasis'
prefix.dash('text-emphasis'); // -> '-webkit-text-emphasis'
prefix('color'); // -> 'color'

pxToNum

Turn string like '0px' to number.

query

Parse and stringify url query strings.

parse

Parse a query string into an object.

Name	Type	Desc
str	string	Query string
return	object	Query object

stringify

Stringify an object into a query string.

Name	Type	Desc
obj	object	Query object
return	string	Query string

query.parse('foo=bar&eruda=true'); // -> {foo: 'bar', eruda: 'true'}
query.stringify({foo: 'bar', eruda: 'true'}); // -> 'foo=bar&eruda=true'
query.parse('name=eruda&name=eustia'); // -> {name: ['eruda', 'eustia']}

repeat

Repeat string n-times.

Name	Type	Desc
str	string	String to repeat
n	number	Repeat times
return	string	Repeated string

repeat('a', 3); // -> 'aaa'
repeat('ab', 2); // -> 'abab'
repeat('*', 0); // -> ''

restArgs

This accumulates the arguments passed into an array, after a given index.

Name	Type	Desc
function	function	Function that needs rest parameters
[startIndex]	number	The start index to accumulates
return	function	Generated function with rest parameters

const paramArr = restArgs(function (rest) { return rest });
paramArr(1, 2, 3, 4); // -> [1, 2, 3, 4]

rmCookie

Loop through all possible path and domain to remove cookie.

Name	Type	Desc
key	string	Cookie key

rmCookie('test');

root

Root object reference, global in nodeJs, window in browser.

rtrim

Remove chars or white-spaces from end of string.

Name	Type	Desc
str	string	String to trim
[chars]	string array	Characters to trim
return	string	Trimmed string

rtrim(' abc  '); // -> ' abc'
rtrim('_abc_', '_'); // -> '_abc'
rtrim('_abc_', ['c', '_']); // -> '_ab'

safeCb

Create callback based on input value.

safeGet

Get object property, don't throw undefined error.

Name	Type	Desc
obj	object	Object to query
path	array string	Path of property to get
return	*	Target value or undefined

const obj = {a: {aa: {aaa: 1}}};
safeGet(obj, 'a.aa.aaa'); // -> 1
safeGet(obj, ['a', 'aa']); // -> {aaa: 1}
safeGet(obj, 'a.b'); // -> undefined

safeStorage

Safe localStorage and sessionStorage.

slice

Create slice of source array or array-like object.

Name	Type	Desc
array	array	Array to slice
[start=0]	number	Start position
[end=array.length]	number	End position, not included

slice([1, 2, 3, 4], 1, 2); // -> [2]

some

Check if predicate return truthy for any element.

Name	Type	Desc
obj	array object	Collection to iterate over
predicate	function	Function to invoked per iteration
ctx	*	Predicate context
return	boolean	True if any element passes the predicate check

some([2, 5], function (val) {
    return val % 2 === 0;
}); // -> true

splitCase

Split different string case to an array.

Name	Type	Desc
str	string	String to split
return	array	Result array

splitCase('foo-bar'); // -> ['foo', 'bar']
splitCase('foo bar'); // -> ['foo', 'bar']
splitCase('foo_bar'); // -> ['foo', 'bar']
splitCase('foo.bar'); // -> ['foo', 'bar']
splitCase('fooBar'); // -> ['foo', 'bar']
splitCase('foo-Bar'); // -> ['foo', 'bar']

startWith

Check if string starts with the given target string.

Name	Type	Desc
str	string	String to search
prefix	string	String prefix
return	boolean	True if string starts with prefix

startWith('ab', 'a'); // -> true

stringify

JSON stringify with support for circular object, function etc.

Undefined is treated as null value.

Name	Type	Desc
obj	object	Object to stringify
spaces	number	Indent spaces
return	string	Stringified object

stringify({a: function () {}}); // -> '{"a":"[Function function () {}]"}'
const obj = {a: 1, b: {}};
obj.b = obj;
stringify(obj); // -> '{"a":1,"b":"[Circular ~]"}'

stringifyAll

Stringify object into json with types.

Name	Type	Desc
obj	*	Object to stringify
[options]	object	Stringify options
return	string	Stringified object

Available options:

Name	Type	Desc
unenumerable=false	boolean	Include unenumerable keys
symbol=false	boolean	Include symbol keys
accessGetter=false	boolean	Access getter value
timeout=0	number	Timeout of stringify
depth=0	number	Max depth of recursion
[ignore]	array	Values to ignore

When time is out, all remaining values will all be "Timeout".

stringifyAll(function test() {}); // -> '{"value":"function test() {}","type":"Function",...}'

stripHtmlTag

Strip html tags from a string.

Name	Type	Desc
str	string	String to strip
return	string	Result string

stripHtmlTag('<p>Hello</p>'); // -> 'Hello'

toArr

Convert value to an array.

Name	Type	Desc
val	*	Value to convert
return	array	Converted array

toArr({a: 1, b: 2}); // -> [{a: 1, b: 2}]
toArr('abc'); // -> ['abc']
toArr(1); // -> [1]
toArr(null); // -> []

toInt

Convert value to an integer.

Name	Type	Desc
val	*	Value to convert
return	number	Converted integer

toInt(1.1); // -> 1
toInt(undefined); // -> 0

toNum

Convert value to a number.

Name	Type	Desc
val	*	Value to process
return	number	Result number

toNum('5'); // -> 5

toSrc

Convert function to its source code.

Name	Type	Desc
fn	function	Function to convert
return	string	Source code

toSrc(Math.min); // -> 'function min() { [native code] }'
toSrc(function () {}) // -> 'function () { }'

toStr

Convert value to a string.

Name	Type	Desc
val	*	Value to convert
return	string	Result string

toStr(null); // -> ''
toStr(1); // -> '1'
toStr(false); // -> 'false'
toStr([1, 2, 3]); // -> '1,2,3'

trim

Remove chars or white-spaces from beginning end of string.

Name	Type	Desc
str	string	String to trim
chars	string array	Characters to trim
return	string	Trimmed string

trim(' abc  '); // -> 'abc'
trim('_abc_', '_'); // -> 'abc'
trim('_abc_', ['a', 'c', '_']); // -> 'b'

tryIt

Run function in a try catch.

Name	Type	Desc
fn	function	Function to try catch
[cb]	function	Callback

tryIt(function () {
    // Do something that might cause an error.
}, function (err, result) {
    if (err) console.log(err);
});

type

Determine the internal JavaScript Class of an object.

Name	Type	Desc
val	*	Value to get type
lowerCase=true	boolean	LowerCase result
return	string	Type of object

type(5); // -> 'number'
type({}); // -> 'object'
type(function () {}); // -> 'function'
type([]); // -> 'array'
type([], false); // -> 'Array'
type(async function () {}, false); // -> 'AsyncFunction'

types

Used for typescript definitions only.

ucs2

UCS-2 encoding and decoding.

encode

Create a string using an array of code point values.

Name	Type	Desc
arr	array	Array of code points
return	string	Encoded string

decode

Create an array of code point values using a string.

Name	Type	Desc
str	string	Input string
return	array	Array of code points

ucs2.encode([0x61, 0x62, 0x63]); // -> 'abc'
ucs2.decode('abc'); // -> [0x61, 0x62, 0x63]
'𝌆'.length; // -> 2
ucs2.decode('𝌆').length; // -> 1

uniqId

Generate a globally-unique id.

Name	Type	Desc
[prefix]	string	Id prefix
return	string	Globally-unique id

uniqId('eusita_'); // -> 'eustia_xxx'

unique

Create duplicate-free version of an array.

Name	Type	Desc
arr	array	Array to inspect
[compare]	function	Function for comparing values
return	array	New duplicate free array

unique([1, 2, 3, 1]); // -> [1, 2, 3]

upperFirst

Convert the first character of string to upper case.

Name	Type	Desc
str	string	String to convert
return	string	Converted string

upperFirst('red'); // -> Red

utf8

UTF-8 encoding and decoding.

encode

Turn any UTF-8 decoded string into UTF-8 encoded string.

Name	Type	Desc
str	string	String to encode
return	string	Encoded string

decode

Turn any UTF-8 encoded string into UTF-8 decoded string.

Name	Type	Desc
str	string	String to decode
safe=false	boolean	Suppress error if true
return	string	Decoded string

utf8.encode('\uD800\uDC00'); // ->  '\xF0\x90\x80\x80'
utf8.decode('\xF0\x90\x80\x80'); // -> '\uD800\uDC00'

values

Create an array of the own enumerable property values of object.

Name	Type	Desc
obj	object	Object to query
return	array	Array of property values

values({one: 1, two: 2}); // -> [1, 2]

viewportScale

Get viewport scale.

viewportScale(); // -> 3

wrap

Wrap the function inside a wrapper function, passing it as the first argument.

Name	Type	Desc
fn	function	Function to wrap
wrapper	function	Wrapper function
return	function	New function

const p = wrap(escape, function(fn, text) {
    return '<p>' + fn(text) + '</p>';
});
p('You & Me'); // -> '<p>You &amp; Me</p>'