TypeError: __require.resolve is not a function

[mvrlin]

Hello! I have an issue with the tsup, I have a TypeScript project with require.resolve function, with pure tsc it works, but when I try to build with tsup-node I get this error:

TypeError: __require.resolve is not a function

I made a reproduction repo for this issue:
https://github.com/mvrlin/tsup-require-resolve

I came across this "solution":

// Before
var __require = (x) => {
  if (typeof require !== "undefined")
    return require(x);
  throw new Error('Dynamic require of "' + x + '" is not supported');
};

// After
var __require = (x) => {
  throw new Error('Dynamic require of "' + x + '" is not supported');
}

if (typeof require !== "undefined") {
  __require = require
}

[hyrious]

The __require is emitted by esbuild if the format is NOT cjs. I think cli-node.ts should add a flag to do that.

Your "solution" about __require is a good advice. I think you can post it to esbuild.

[anymaniax]

Hello! I had the same problem at the moment I just disable the code splitting to have the code working. Did you have another solution?

[screetBloom]

Share my solution

"scripts": {
-  "build": "tsup"
+  "build": "tsup && node fix.js"
}

// fix.js
const beforeStr = `var __require = (x) => {
  if (typeof require !== "undefined")
    return require(x);
  throw new Error('Dynamic require of "' + x + '" is not supported');
};`
const replacedContent = `
  ${beforeStr}
  if (typeof require !== "undefined") {
    __require = require
  }
`

const res = str.replace(beforeStr, replacedContent)

[screetBloom]

After reading the source code of tsup, I found that there is workaround

"scripts": {
-  "build": "tsup"
+  "build": "tsup --format cjs --no-splitting"
}

Using --format alone won't work, you need --no-splitting

Then the code can go to output as expected

[hyrious]

@screetBloom Yes that should work, but it will lose code splitting.

[screetBloom]

@screetBloom Yes that should work, but it will lose code splitting.

Yes, but code splitting in esbuild must be esm

When we userequire, it's usually in the node side

[screetBloom]

But admittedly, esbuild's default __require does need to be fixed

[screetBloom]

Also I think splitting should be false when format === 'cjs', And should be enabled by default when format is esm

[hyrious]

Since esbuild 0.12.26, this issue should be solved automatically by updating dependencies. (npm update)
@mvrlin Can you confirm that?

[mvrlin]

@hyrious Yes, working as expected! Thank you!