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							- 'use strict';
 
- module.exports = function () {
 
- 	var weakMap, x;
 
- 	if (typeof WeakMap !== 'function') return false;
 
- 	try {
 
- 		// WebKit doesn't support arguments and crashes
 
- 		weakMap = new WeakMap([[x = {}, 'one'], [{}, 'two'], [{}, 'three']]);
 
- 	} catch (e) {
 
- 		return false;
 
- 	}
 
- 	if (String(weakMap) !== '[object WeakMap]') return false;
 
- 	if (typeof weakMap.set !== 'function') return false;
 
- 	if (weakMap.set({}, 1) !== weakMap) return false;
 
- 	if (typeof weakMap.delete !== 'function') return false;
 
- 	if (typeof weakMap.has !== 'function') return false;
 
- 	if (weakMap.get(x) !== 'one') return false;
 
- 	return true;
 
- };
 
 
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