babel如何实施Set / Map polyfills [英] How does babel implement Set / Map polyfills

问题描述

我的问题与巴别塔的Set / Map，弱集/弱地图polyfills的计算复杂性有关？ Afaik没有ES5语言功能允许直接实现Set / Map，因此可能会发生Set / Map可能使用引擎框架下的数组结构来实现对象引用的查找，这将产生O（N）查找性能。所以问题是：

My question is related to computational complexity of Set / Map, Weak Set / Weak Map polyfills by Babel? Afaik there are no ES5 language features allowing to implement Set / Map directly, and so it might happen that Set / Map might use Array structure under the hood to implement lookup by object reference which would yield to O(N) lookup performance. And so the question is:

Set / Map查找操作的计算复杂度是多少？

What is the computational complexity of Set / Map lookup operations?

谢谢提前！

推荐答案

Babel使用core-js作为其polyfill，从 GitHub repo ：

Babel uses core-js for its polyfill, from the GitHub repo:

核心-js在大多数情况下使用本地集合，只需修复方法/
构造函数（如果需要），并且在旧环境中使用快速
polyfill （O（1）lookup） / p>

core-js uses native collections in most case, just fixes methods / constructor, if it's required, and in old environment uses fast polyfill (O(1) lookup).

_{（Emphasis mine）}

您对确切的查找感兴趣，它位于这个文件。它不是由数组支持。

And if you're interested in the exact lookup, it's in this file. It's not backed by an array.

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