webpack: globalObject: "this" work incorrect with ModuleFederation after 5.2.0

Bug report

What is the current behavior? the ModuleFederation crashed with output.globalObject: "this"

If the current behavior is a bug, please provide the steps to reproduce.

clone https://github.com/module-federation/module-federation-examples/tree/master/basic-host-remote
add ModuleFederationPlugin
set output.globalObject: "this"
set package.json (disable arrowFunctions)

"browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }

build and run

the output remoteEntry.js error:

// this is undefined
var chunkLoadingGlobal = this["webpackChunkreact_app_shared"] = this["webpackChunkreact_app_shared"] || [];

What is the expected behavior?

ModuleFederation should works correct with: output.globalObject: "this"

Other relevant information: webpack version: 5.2.0~5.5.1

About this issue

Original URL
State: open
Created 4 years ago
Comments: 24 (21 by maintainers)

Most upvoted comments

My case: First i found complied code contains arrow fucntion. so i add target: ['web', 'es5'] to solve the problem. Then code became:

! function () {
  "use strict";
  /* `this` is undefined in strict mode */
  n = this.webpackChunkFoo = this.webpackChunkFoo || []
}

So i need to add output.globalObject: 'window' to solve this problem.

But it seems a little weird because once you set target: ['web', 'es5']. You need to configure output.globalObject: 'window' too. Which is not mentioned in documentation.

Edge00 on Jun 18, 2021

It could be indeed a bug. Sounds like the bundle becomes strict mode only and this is undefined in strict mode.

As workaround avoid this as global object. Using the default should be fine instead.

sokra on Nov 25, 2020

Still an issue probably.

RReverser on Nov 13, 2022

I think we should not use arrow function in some cases

we use it only if environment supports it.

vankop on Apr 12, 2022

Yeah I guess that works as a workaround - in my case I went ahead and updated that legacy Worker that caused an issue to be strict mode compliant.

I just wanted to report this as it will probably catch others by surprise too, and takes a while to debug what’s happening.

I think Webpack should either skip non-module usages of Workers, or provide correct environment to them, or at least warn on such usages - current behaviour quietly emits broken code, which seems like the worst of those options DX-wise.

RReverser on May 10, 2021