Typescript errors with Webpack 5

Webpack 5 (5.0.0-beta.16) does not export Plugin, which cause type-checking and builds to fail with:

node_modules/nodemon-webpack-plugin/dist/index.d.ts:3:12 - error TS2459: Module '"......./node_modules/webpack/types"' declares 'Plugin' locally, but it is not exported.

3   import { Plugin } from 'webpack';
             ~~~~~~

  node_modules/webpack/types.d.ts:5126:19
    5126 declare interface Plugin {
                           ~~~~~~
    'Plugin' is declared here.

node_modules/schema-utils/declarations/validate.d.ts:2:34 - error TS2307: Cannot find module 'json-schema'.

2 export type JSONSchema4 = import('json-schema').JSONSchema4;
                                   ~~~~~~~~~~~~~

node_modules/webpack/types.d.ts:62:8 - error TS2307: Cannot find module 'estree'.

62 } from "estree";

Related:

• https://github.com/webpack/webpack/issues/10757#issuecomment-625542931
• https://github.com/webpack/webpack/issues/9802

[Izhaki]

The typings issue was declared by the WebPack team as a breaking change between v4 and v5.

We have two options:

1. Split the plugin.
2. Create our own types (like html-webpack-plugin did).

Second option seems far more reasonable to me.

Will attempt fix in due course.

[Izhaki]

// This throws an error with my setup and TypeScript config.
import NodemonPlugin from 'nodemon-webpack-plugin';

I’m afraid this has to do with the whole CommonJS/ES6 mismatch, and I’ve documented this in the type definitions:

// We prioritise supporting CommonJS than ES6 syntax here.
// Typescript users will have to add `esModuleInterop` in `compilerOptions`.
// https://www.typescriptlang.org/docs/handbook/modules.html#export--and-import--require
export = NodemonPlugin;

Basically, you need to choose between CommonJS (export =) and ES6 (export default). If you opt for the latter, than CommonJS scripts will have to import the plugin like this (note .default):

const NodemonPlugin = require('nodemon-webpack-plugin').default; 

I’ve prioritise the CommonJS export based on a (rather reasonable in my view) assumption that most users don’t have their webpack.config.js transpiled.