Adding a value to a map in typescript

Question

I must be missing something here. I try to put a value into a map but it doesn't want to work.

const tempMap = new Map();
tempMap.set("bla", "bla");
console.log(tempMap)
--> output: {}

Can someone explain to me why it is like that? Shouldn't the output have the added value in it?

Try it yourself in the playground.

The value is added. Try logging Array.from(tempMap.keys()) or Array.from(tempMap.values()) — Evan Trimboli
– Evan Trimboli, Commented Nov 11, 2020 at 11:23

StPaulis · Accepted Answer · 2020-11-11 11:46:14Z

3

The class itself won't export any values, use should use the API

You want to do something like this:

let tmpMap = new Map();
tmpMap.set("bla", "bla");
console.log(tmpMap.get('bla')); // bla

You can also iterate in tempMap.keys() or tempMap.values() like @Evan already commented.

edited Nov 11, 2020 at 11:46

answered Nov 11, 2020 at 11:30

StPaulis

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3 Comments

gausss Over a year ago

Thanks for the explanation :) looks like I've still got some way left with Typescript and how these types really work.

gausss Over a year ago

In the end I like to serialize this map to session storage e.g. sessionStorage.setItem("some_key", JSON.stringify(tmpMap));. I could get all the values, but do you have a suggestion on how to serialize the object as a whole?

StPaulis Over a year ago

If you want to use the object itself, maybe Map is not what you looking for. You can create an custom interface and use typescriptlang.org/docs/handbook/…

gausss · Accepted Answer · 2020-11-11 14:47:36Z

0

In the end I used the Record type for my purpose. Which is a kind of dictionary type.

answered Nov 11, 2020 at 14:47

gausss

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