Fetch Variable from String (JavaScript)

Question

Suppose I have a few variables:

a = 1
b = 2
c = 3
d = 4
vars = ['a', 'b', 'c', 'd'] // Values of them stored in a list

Now, I have a for loop:

for (i = 0; i < vars.length; i ++){
    console.log(vars[i]);
}

Here, the output would be a,b,c,d but what I'm willing to get is 1,2,3,4.

Note: The vars list should remain the same. This is just an example of what I'm trying to do...

Any idea on how we could fetch the variable just by a string name (given that the string name is exactly the same as the variable name)?

Duplicate [Get global variable dynamically by name string in JavaScript](https://stackoverflow.com/questions/1920867/get-global-variable-dynamically-by-name-string-in-javascript) — esqew, Oct 21 '22 at 13:14
Also your variables should be **declared** with `let`, `const`, or (if really necessary) `var`. — Pointy, Oct 21 '22 at 13:14
Also, see ["Variable" variables in JavaScript](/q/5187530/4642212). In practice, you never need — or _want_, really — dynamic variable names. Use a simple object instead: `const obj = { a: 1, b: 2, c: 3, d: 4 };` … `console.log(obj[vars[i]]);`. — Sebastian Simon, Oct 21 '22 at 13:23
I simply stated a normal example and I am aware of variable declaration. I don't want the list to be changed simply. — The Myth, Oct 21 '22 at 13:26
@Pointy I would like to fetch the user page and based upon that I have variables which I would like to run in a function (without if conditions). — The Myth, Oct 21 '22 at 13:27
The idiomatic JavaScript approach would be to have an object contain properties, which can be accessed by a name that's computed somehow, like `object["a"]`. — Pointy, Oct 21 '22 at 13:45
@Pointy it won't work in my case since I'll also end up with `undefined` or null strings. — The Myth, Oct 22 '22 at 10:53
Well how would you expect things to work with `undefined` or `null` strings if you were gaining access to plain variables somehow? — Pointy, Oct 22 '22 at 11:04
I was trying to fetch the page user is on for animation purposes, I've done it now :) — The Myth, Oct 22 '22 at 11:19

Matt Ellen · Accepted Answer · 2022-10-21T13:16:42.533

0

I am assuming you're working in a browser.

Since a, b, c, and d are global variables, you can get them from the window object:

a = 1
b = 2
c = 3
d = 4
vars = ['a', 'b', 'c', 'd'] // Values of them stored in a list

for (i = 0; i < vars.length; i ++){
    console.log(window[vars[i]]);
}

edited Oct 21 '22 at 13:16

answered Oct 21 '22 at 13:15

Matt Ellen

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Assuming a browser environment. – tadman Oct 21 '22 at 13:15

Fetch Variable from String (JavaScript)

1 Answers1