How can I construct a variable in JavaScript based on another variables value? And How can I reassign it's value and perform methods on that variable? [duplicate]

Question

I want to be able to basically do this

let x = 1;
let `arr${x}`;

if ((i = 0)) `arr${x}` = [];
`arr${x}`.push(words);
console.log(`arr${x}`);

I have tried using eval()

let x = 1;
eval(`let arr${x}`);

if ((i = 0)) eval(`arr${x} = [];`);
eval(`arr${x}.push(${words})`);
console.log(eval(`arr${x}`));

But it's giving an error: Uncaught ReferenceError: arr1 is not defined In this line: eval(arr${x}.push(${words}));

eval is the only way, JS doesn't have a concept of dynamically created variable names. I'd suggest you to use a suitable data structure instead (ex. object). Notice, that i = 0 in the conditions doesn't do what you think it does. — Teemu
– Teemu, Commented May 14, 2024 at 5:41
@Teemu Here is a link to codepen for the whole code, so you would understand better of what I'm trying to do: codepen.io/huz3y/pen/yLWNedW — huz3y
– huz3y, Commented May 14, 2024 at 5:51
Why not add that code right in the question, instead of linking it, as a Stack snippet? — connexo
– connexo, Commented May 14, 2024 at 5:55

connexo · Accepted Answer · 2024-05-14 05:50:15Z

1

You can't do this with variables, but you can very well do it with object properties. If the object you create it on happens to be the global object (window in browsers) this will also create a global variable:

let x = 1, words = "some words here", i = 0;
window[`arr${x}`] = undefined;

if (i===0) window[`arr${x}`] = [];
window[`arr${x}`].push(words);
console.log(window[`arr${x}`]);
console.log(arr1);

answered May 14, 2024 at 5:50

connexo

57.2k15 gold badges112 silver badges149 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

huz3y Over a year ago

This was what I was looking for!! You managed to answer me eventhough I gave very little context. Thanks

Collectives™ on Stack Overflow

How can I construct a variable in JavaScript based on another variables value? And How can I reassign it's value and perform methods on that variable? [duplicate]

1 Answer 1

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Linked

Related