What is the reason for Map not having a map function available?

I'm puzzled by the fact that in order to utilize a Map object, it's necessary to destructure it into an array of arrays first. This process feels counterintuitive.

Could someone shed light on the reasoning behind this design choice? I'm aware that languages like Scala have map methods for Maps, so I'm curious as to why JavaScript lacks this feature.

The syntax appears unnecessarily complex and verbose:

let mappedMap = new Map( 
  [...originalMap]
  .map(([k, v]) => [k * 2, '_' + v])
);

Wouldn't it make more sense to have a simpler approach like this?

let mappedMap = originalMap.map((k, v) => [k * 2, '_' + v]);

Answer №1

In the world of ES6, Maps are portrayed as iterables with a key/value structure. The map function on arrays generates a fresh array, but I wonder if it is feasible to create a new version in that manner. Personally, I prefer using forEach for Maps and creating fresh ones from there. Additionally, if you're looking for similar functionality, I suggest exploring immutable.js

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