feat(console): $x utility

doc/UTIL_API.md

@@ -2741,3 +2741,16 @@ const p = wrap(escape, function(fn, text) {
 });
 p('You & Me'); // -> '<p>You &amp; Me</p>'
 ```
+
+## xpath 
+
+Select elements using xpath, IE is not supported.
+
+|Name  |Type  |Desc           |
+|------|------|---------------|
+|xpath |string|Xpath          |
+|return|array |Target elements|
+
+```javascript
+xpath('//html/body'); // -> [body]
+```

src/Console/Logger.js

@@ -20,7 +20,8 @@ import {
   keys,
   last,
   throttle,
-  raf
+  raf,
+  xpath
 } from '../lib/util'
 
 let id = 0
@@ -73,6 +74,9 @@ export default class Logger extends Emitter {
       $$() {
         return toArr(document.querySelectorAll.apply(document, arguments))
       },
+      $x(path) {
+        return xpath(path)
+      },
       clear: () => {
         this.clear()
       },

src/lib/util.js

@@ -8952,4 +8952,42 @@ export var wrap = _.wrap = (function (exports) {
     return exports;
 })({});
 
+/* ------------------------------ xpath ------------------------------ */
+
+export var xpath = _.xpath = (function (exports) {
+    /* Select elements using xpath, IE is not supported.
+     *
+     * |Name  |Type  |Desc           |
+     * |------|------|---------------|
+     * |xpath |string|Xpath          |
+     * |return|array |Target elements|
+     */
+
+    /* example
+     * xpath('//html/body'); // -> [body]
+     */
+
+    /* typescript
+     * export declare function xpath(xpath: string): HTMLElement[];
+     */
+    exports = function(xpath) {
+        var ret = [];
+        var nodesSnapshot = document.evaluate(
+            xpath,
+            document,
+            null,
+            XPathResult.ORDERED_NODE_SNAPSHOT_TYPE,
+            null
+        );
+
+        for (var i = 0; i < nodesSnapshot.snapshotLength; i++) {
+            ret.push(nodesSnapshot.snapshotItem(i));
+        }
+
+        return ret;
+    };
+
+    return exports;
+})({});
+
 export default _;