get name of input variable (like Function.name)

Question

I have a Function in which I want to retrieve the name of the variable that was used to call the function. How can I do that?

let fooVar = 3;
let barVar = "hello World";

function doStuff(variable) {
    let varName = ???; // retrieve name of variable
    return varName + ": " + variable;
}

document.write(doStuff(fooVar)); // should output "fooVar: 3"
document.write(doStuff(barVar)); // should output "barVar: hello World"

If variable was a Function, I could use variable.name.

I am aware of this, but it will only return "variable", not the name of the variable that was put into the function.

As an alternative: Is there a way to AUTOMATICALLY call a certain function whenever a variable is declared? If that was possible, I'd use the approach given in the link above to add the variable name to a map, then utilize that map inside the function to retrieve variable name.

Does this answer your question? Variable name as a string in Javascript — Simone Rossaini
– Simone Rossaini, Commented Nov 3, 2021 at 12:40
@SimoneRossaini no. I linked an answer to that question and explained why it does not help. — Kjara
– Kjara, Commented Nov 3, 2021 at 12:46
Yes true, it's impossible because you change name of variable into function so you must use object — Simone Rossaini
– Simone Rossaini, Commented Nov 3, 2021 at 12:50

AnanthDev · Accepted Answer · 2021-11-03 12:58:08Z

1

That's actually impossible to do, as a workaround you can do something like this

let fooVar = { name: 'fooVar', value: 3 };
let barVar = { name: 'barVar', value: 'Hello World' };

function doStuff({ name, value }) {
    let varName = name; // retrieve name of variable
    return varName + ": " + value;
}

console.log(doStuff(fooVar)); // should output "fooVar: 3"
console.log(doStuff(barVar));

or you can do

let fooVar = 3;
let barVar = 'Hello World';

function doStuff(variable) {
    const arr = Object.entries(variable)[0];
    const [name, value] = arr;
    let varName = name; // retrieve name of variable
    return varName + ": " + value;
}

console.log(doStuff({ fooVar })); // should output "fooVar: 3"
console.log(doStuff({ barVar }));

edited Nov 3, 2021 at 12:58

answered Nov 3, 2021 at 12:50

AnanthDev

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2 Comments

Kjara Over a year ago

Second workaround solves my problem, thanks!

AnanthDev Over a year ago

No problem, please consider marking it as a correct answer if it helped :)

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