Preset conflicting with jest --watch

[tim-rohrer]

I've been working with ESM for a while. Changes to Jest and my own understanding have caused me to try and thin my projects, to go to a more minimal number of npm install commands. It also caused me to better understand how to I should be able to use this present and ESM together. My jest.config.ts now looks like this:

import type { JestConfigWithTsJest } from "ts-jest"

const config: JestConfigWithTsJest = {
  preset: "@shelf/jest-mongodb",
  extensionsToTreatAsEsm: [".ts"],
  verbose: true,
  rootDir: "src",
  moduleNameMapper: {
    "^(\\.{1,2}/.*)\\.js$": "$1",
  },
  transform: {
    // '^.+\\.[tj]sx?$' to process js/ts with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process js/ts/mjs/mts with `ts-jest`
    "^.+\\.tsx?$": [
      "ts-jest",
      {
        useESM: true,
      },
    ],
  },
  fakeTimers: {
    enableGlobally: true,
    doNotFake: ["nextTick", "setImmediate"],
  },
}

export default config

In the past, I didn't understand that I could use this preset with ESM, but I realize I can if I configure ts-jest as above.

What I found was that NODE_OPTIONS=--experimental-vm-modules npx jest --watch results in tests being run over and over again without me changing any files. It simply repeats.

jest does work without --watch. Through trial and error, if I remove preset: "@shelf/jest-mongodb".

I'll go back to manually configuring the mongdb memory server, but if someone sees something obviously wrong with my configuration, please let me know.

[thinh-kieu]

I also encountered a similar issue when upgrading jest-mongodb from version 2 to version 4. When I reread the documentation, I found that this issue had already been mentioned and resolved by ignoring globalConfig. You can check the guide here: https://www.npmjs.com/package/@shelf/jest-mongodb#6-jest-watch-mode-gotcha.

// jest.config.js
module.exports = {
  watchPathIgnorePatterns: ['globalConfig'],
};