Diagnostics option

The diagnostics option configures error reporting. It can both be enabled/disabled entirely or limited to a specific type of errors and/or files.

If a diagnostic is not filtered out, ts-jest will fail the compilation and your test.

Disabling/enabling

By default all diagnostics are enabled. This is the same as setting the diagnostics option to true. To disable all diagnostics, set diagnostics to false. This might lead to slightly better performance, especially if you're not using Jest's cache.

Advanced configuration

The diagnostics option's value can also accept an object for more advanced configuration. Each config. key is optional:

• warnOnly: If specified and true, diagnostics will be reported but won't stop compilation (default: disabled).
• ignoreCodes: List of TypeScript error codes to ignore. Complete list can be found there. By default here are the ones ignored:
  • 6059: 'rootDir' is expected to contain all source files.
  • 18002: The 'files' list in config file is empty. (it is strongly recommended including this one)
  • 18003: No inputs were found in config file.
• exclude: If specified, diagnostics of source files which path matches will be ignored. This works a bit similar to tsconfig option exclude with the only difference is that in TypeScript, exclude will also exclude files from compilation process.
• pretty: Enables/disables colorful and pretty output of errors (default: enabled).

Examples

Disabling diagnostics

jest.config.ts

import type { Config } from 'jest'

const jestConfig: Config = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        diagnostics: false,
      },
    ],
  },
}

export default jestConfig

Advanced options

Enabling diagnostics for test files only

Assuming all your test files ends with .spec.ts or .test.ts, using the following config will enable error reporting only for those files:

jest.config.ts

import type { Config } from 'jest'

const jestConfig: Config = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        diagnostics: {
          exclude: ['!**/*.(spec|test).ts'],
        },
      },
    ],
  },
}

export default jestConfig

Do not fail on first error

While some diagnostics are stop-blockers for the compilation, most of them are not. If you want the compilation (and so your tests) to continue when encountering those, set the warnOnly to true:

jest.config.ts

import type { Config } from 'jest'

const jestConfig: Config = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        diagnostics: {
          warnOnly: true,
        },
      },
    ],
  },
}

export default jestConfig

Ignoring some error codes

All TypeScript error codes can be found there. The ignoreCodes option accepts this values:

1. A single number (example: 1009): unique error code to ignore
2. A string with a code (example "1009", "TS1009" or "TS1009")
3. A string with a list of the above (example: "1009, TS2571, 4072")
4. An array of one or more from 1 or 3 (example: [1009, "TS2571", "6031"])

jest.config.ts

import type { Config } from 'jest'

const jestConfig: Config = {
  // [...]
  transform: {
    // '^.+\\.[tj]sx?$' to process ts,js,tsx,jsx with `ts-jest`
    // '^.+\\.m?[tj]sx?$' to process ts,js,tsx,jsx,mts,mjs,mtsx,mjsx with `ts-jest`
    '^.+\\.tsx?$': [
      'ts-jest',
      {
        diagnostics: {
          ignoreCodes: [2571, 6031, 18003],
        },
      },
    ],
  },
}

export default jestConfig