avoid Array.from and Reflect #9
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loganfsmyth
reviewed
May 10, 2017
| a.__proto__ = b; | ||
| }); | ||
| var getPrototypeOf = Object.getPrototypeOf || (function getPrototypeOf(a)) { | ||
| return a.__proto__; |
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I can't imagine a case where getPrototypeOf doesn't exist but __proto__ does. getPrototypeOf is from ES5, so it either exists, or there's no way to polyfill it AFAIK.
loganfsmyth
reviewed
May 10, 2017
| function ExtendableBuiltin(){ | ||
| // Not passing "newTarget" because core-js would fall back to non-exotic | ||
| // object creation. | ||
| var instance = Reflect.construct(cls, Array.from(arguments)); | ||
| Object.setPrototypeOf(instance, Object.getPrototypeOf(this)); | ||
| var instance = new (Function.prototype.bind.apply(cls, arguments))(); |
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The general concern with approaches like this is that .bind is known to be slow. Most things optimize this like statements like https://github.com/zloirock/core-js/blob/master/modules/es6.reflect.construct.js#L29, so larger code like that was what I was trying to avoid.
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