the result of resolve tslib is diffrent from webpack

[underfin]

Description

The tslib package.json condition exports has a module filed.

"exports": {
      ".": {
          "module": "./tslib.es6.js",
          "import": "./modules/index.js",
          "default": "./tslib.js"
      },
      "./": "./"
  }

It can be webpack used and keep bundle result correctly, but esbuild is not (esbuild use import).

Reproduction

https://github.com/underfin/bug-reporter/tree/master/esbuild-tslib

• pnpm i && npm run build

esbuild output https://github.com/underfin/bug-reporter/blob/master/esbuild-tslib/esbuild-output.js#L454

webpack output https://github.com/underfin/bug-reporter/blob/master/esbuild-tslib/webpack-output/main.js#L23

Maybe helpers issue

• Add module condition, so webpack loads es6 module version microsoft/tslib#129
• 5.0.0-rc.3 fails with tslib webpack/webpack#11613

[hyrious]

module is not a formal field of node's exports, see Conditional exports in the doc. esbuild won't support that.

I'll suggest that they use this pattern to force bundling the same file when targetting browser:

"exports": {
  ".": {
    "node": {
      "import": "./modules/index.js",
      "require": "./tslib.js"
    },
    "default": "./tslib.es6.js"
  }
}

On the other hand, you can write a plugin to force resolving to the file you want.

[evanw]

The name module is meaningless here. The standard doesn’t specify any special behavior for it. You can give it meaning using --conditions=module if you’d like: https://esbuild.github.io/api/#conditions.