如何在任何对象上使用ES6哈希映射，而不需要引用（即Java哈希码） [英] How to use ES6 Hash Map on any object without maintaing a reference (I.e. Java hashcode)

问题描述

我一直在io.js中尝试使用ES6 Map，并意识到我无法执行以下操作：

I've been experimenting with ES6 Map in io.js and realized that I can't do the following:

var map = new Map()
map.set( {key:"value"}, "some string");
map.get( {key:"value"} ); // undefined. I want "some string"

这是因为{key：value} === {key ：value}是false。

This is because {key:"value"} === {key:"value"} is false.

我需要能够使用一个对象作为关键字，但不需要ACTUAL对象来查找值，就像Java HashMap使用的方式哈希码和等于。这是可能的吗？

I need to be able to use an object as a key but not require the ACTUAL object to lookup the value like how java HashMap uses hashcode and equals. Is this possible?

推荐答案

• 如果缺少对象标识来源于序列化反序列化往返给他们一个唯一的ID，幸存下来，并使用该ID作为键


• 从其属性子集中计算一个键，如果您可以确定剩余属性取决于该子集或与您的操作无关


• 实现自己的散列图和对象散列。这可能会使主机对象变得棘手，但应该是相当简单的JSON兼容数据


• JSON获取或设置之前的JSON编码。这是非常低效的，只适用于JSON可序列化的对象。但是比以前的选项更容易实现


• If the lack of object identity stems from a serialize-deserialize roundtrip just give them a unique ID that survives that and use that ID as key
• calculate a key from a subset of its properties if you can be certain that the remaining properties either depend on that subset or are irrelevant to your operation
• implement your own hash map and object hashing. this can get tricky with host objects but should be fairly simple with JSON-compatible data
• JSON-encode before each get or set. It's quite inefficient and only works with JSON-serializeable objects. But easier to implement than the previous option

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