This change was prompted due to our jest tests breaking with the following error:

/../frontend/node_modules/d3-array/src/index.js:1

SyntaxError: Unexpected token 'export'

    > 1 | import { bisector } from "d3-array";
        | ^
      2 | 

      at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1726:14)
      at Object.<anonymous> (src/utils.ts:1:1)

Our code seem to import the ESM module but Jest doesn't transform esm modules in node_modules, simply expecting commonjs modules from libraries - causing the error. Changing the main property to the commonjs export fixes the error but still provide ESM modules for the tools that support them.

Thank you for the suggestion. Per the release notes, D3 now only provides ES modules for Node. CommonJS is no longer supported.

Ah, hadn't noticed that - sorry for the noise and thanks for the fast response! 👍

For anyone else stumbling across this question, the solution for us was to set the transformIgnorePatterns in jest.config.js like so:

  transformIgnorePatterns: ["/node_modules/(?!(d3-array|internmap))"],