Can require() statement in commonjs be dynamic?

Question

Is require() statement in commonjs module system static or dymanic? Can require() be dynamic? Can anyone give examples for this?

is following code dynamic or static:

let c1="./c"
let c2=".js";
const f=require(c1+c2);

console.log(f);

I mean will c1+c2 resolved at compile time or run time? I am totally confused with AI answers. Some time it is saying require() is dynamic sometimes it is saying it is static. Still Stackoverflow is best resource.

LLM "AI" systems are not computer programmers. – Pointy Jul 16 '23 at 13:09 — Pointy, Jul 16 '23 at 13:09

Alexander Nenashev · Accepted Answer · 2023-07-16T13:14:02.820

2

It's dynamic, but a module is executed only once like in ESM. It's like a sync version of ESM's import():

let count = 10;
while (count--) {

    const random = ['fs', 'fs2'][Math.floor(Math.random() * 1.9999)];
    console.log('require', random);

    try {
        const fs = require(random);
    } catch (e) {
        console.log(e.message);
    }
}

Each time this throws an error randomly:

require fs2
Cannot find module 'fs2'
Require stack:
 - /bytex/change-color/test.js
require fs
require fs
require fs2
Cannot find module 'fs2'
Require stack:
 - /bytex/change-color/test.js
require fs2
Cannot find module 'fs2'
Require stack:
 - /bytex/change-color/test.js
require fs2
Cannot find module 'fs2'
Require stack:
 - /bytex/change-color/test.js
require fs2
Cannot find module 'fs2'
Require stack:
 - /bytex/change-color/test.js
require fs
require fs2
Cannot find module 'fs2'
Require stack:
 - /bytex/change-color/test.js
require fs2
Cannot find module 'fs2'
Require stack:
 - /bytex/change-color/test.js

edited Jul 16 '23 at 13:14

answered Jul 16 '23 at 13:08

Alexander Nenashev

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Thanks for reply. can u elaborate "but a module is executed only once"? – a Learner Jul 16 '23 at 13:23
JS code inside a module is executed only once – Alexander Nenashev Jul 16 '23 at 13:29
Is using dynamic require() a good practice? or can it cause any problems with bundlers like webpack? – a Learner Jul 16 '23 at 13:35
@aLearner i would suggest to move to ESM (`import`). require is outdated, many new nodejs libraries don't support it. i'm using Vite so can't speak for webpack. But i'm pretty sure webpack supports 'import' too – Alexander Nenashev Jul 16 '23 at 13:39
@aLearner if you find my answer useful please accept it (the checkbox) and upvote (the arrow up), thanks – Alexander Nenashev Jul 16 '23 at 13:40

Can require() statement in commonjs be dynamic?

1 Answers1