.replace is not a function

[jeffersonbenson]

Trying to figure out if this is a bug or just my lack of experience. I'm currently developing a project that utilizes ethers.js which uses bn.js as a dependency. So far I've only imported the library into one of my files and receive the following error attempting to run with wmr --host 0.0.0.0 on my raspberry pi 4. The error I get is the following:

Error bundling bn.js:  TypeError: (iG(...) || "index.js").replace is not a function
    at oG (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:1243297)
    at aG (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:1243618)
    at async Object.resolveId (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:1245002)
    at async wu (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:346845)
    at async Ku.loadEntryModule (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:356260)
    at async Promise.all (index 0) {
  code: 'PLUGIN_ERROR',
  plugin: 'npm-plugin',
  hook: 'resolveId'
}

500 /@npm/bn.js - (iG(...) || "index.js").replace is not a function

  at oG (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:1243297)
  at aG (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:1243618)
  at async Object.resolveId (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:1245002)
  at async wu (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:346845)
  at async Ku.loadEntryModule (/home/pi/starcruiser/node_modules/wmr/wmr.cjs:2:356260)
  at async Promise.all (:-1:-1)

I think I've narrowed it down to being an issue with WMR instead of ethers, but as to what specific component is failing I'm not too sure. Any insight would be greatly appreciated. Thanks in advance!

[rschristian]

The error comes from WMR's module resolution:

wmr/packages/wmr/src/plugins/npm-plugin/resolve.js

Lines 10 to 17 in 9a6777f

	function resolveLegacyEntry(pkg, path) {
	const entry =
	_resolveLegacyEntry(pkg, {
	browser: true,
	fields: ['esmodules', 'modern', 'module', 'jsnext:main', 'browser', 'main']
	}) || 'index.js';
	return '/' + entry.replace(/^\.?\//, '');
	}

It looks like this might be upstream issue in resolve.exports, or perhaps bn.js is using an invalid configuration of the (very loose) "browser" field spec.

bn.js

{
  "browser": {
    "buffer": false
  }
}

entry gets resolve to { buffer: false }, which obviously isn't a module (and throws the .replace is not a function error).

I'll have to poke around a bit.

Edit: Some closer reading of the field spec and resolve.exports's docs show everything is correct upstream, we just don't handle the object return of "browser" correctly. Created #910 for tracking this.

[jeffersonbenson]

Thank you so much! I'll be tracking on the issue as best I can follow. 😁