Polyfills and reflect-metadata

[LIMPIX31]

How do I set up vitest for in-source testing, so that I can use reflect-metadata and prototype extensions for example?

[sheremet-va]

You need to add your source code files to includeSource property in your config:

// vitest.config.ts
export default {
  test: {
    includeSource: ['src/**/utils.ts']
  }
}

And use import.meta.vitest to define tests:

export function add(...args: number[]) {
  return args.reduce((a, b) => a + b, 0)
}

if (import.meta.vitest) {
  const { it, expect } = import.meta.vitest
  it('add', () => {
    expect(add()).toBe(0)
    expect(add(1)).toBe(1)
    expect(add(1, 2, 3)).toBe(6)
  })
}

Docs: https://vitest.dev/guide/in-source.html

[LIMPIX31]

You need to add your source code files to includeSource property in your config:

// vitest.config.ts
export default {
  test: {
    includeSource: ['src/**/utils.ts']
  }
}

And use import.meta.vitest to define tests:

export function add(...args: number[]) {
  return args.reduce((a, b) => a + b, 0)
}

if (import.meta.vitest) {
  const { it, expect } = import.meta.vitest
  it('add', () => {
    expect(add()).toBe(0)
    expect(add(1)).toBe(1)
    expect(add(1, 2, 3)).toBe(6)
  })
}

Docs: https://vitest.dev/guide/in-source.html

It doesn't work.

// src/vitest.env.ts
import 'reflect-metadata'

Number.prototype.map = ...

// vitest.config.ts
export default defineConfig({
  test: {
    includeSource: ['src/**/*.{ts,tsx}', 'src/vitest.env.ts'],
    environment: 'happy-dom',
    coverage: {
      provider: 'istanbul',
    },
  },
})

Error:

this._progress.map is not a function

[LIMPIX31]

?

[shellscape]

it's a shame this never got a followup. looking for the same answer. importing reflect-metadata with includeSource is also not working for me.

[yakirgot]

I did it by creating test-setup.ts file and then including it in setupFiles.