javascript set key in map instead of variable name

Question

why in this code, a is interpreted as real key name, not value hidden under a variable?

function myfunc(a,b)
{
return {a:b};
}

var c = myfunc("key","value");
console.log(c);

This code print:

{
  a: "value"
}

not:

{
  "key": "value"
}

How to modify this code, to use value under a as key name?

Artem Arkhipov · Answer 1 · 2023-06-22T15:24:03.980

0

It happens because {}.a means property a of the object and doesn't refer to any variables you have. In order to use some variable as a key, you need to use [a] instead. You may read more on this topic here.

function myfunc(a,b)
{
  return {[a]:b}; // note I added [ ]
}

edited Jun 22 '23 at 15:24

answered Jun 22 '23 at 15:21

Artem Arkhipov

7,025
5
30
52

hah, I don't know why, but working, Thank You! – sosnus Jun 22 '23 at 15:23
Yes, I want do it, but "You can accept an answer in 8 minutes" PS: thank you for fast response ;) – sosnus Jun 22 '23 at 15:26

score 0 · Answer 2 · answered Jun 22 '23 at 15:22

0

You need to use the [bracket notation] for a computed property name

function myfunc(a, b) {
  return {
    [a]: b
  };
}

var c = myfunc("key", "value");
console.log(c);

answered Jun 22 '23 at 15:22

Samathingamajig

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javascript set key in map instead of variable name

2 Answers2