Jest 命令无法识别

Question

So i just started learning about Test Driven Developement and as an example i was asked to run the command npm test helloWorld.spec.js in the terminal but i got this error:

> javascript-exercises@1.0.0 test
> jest "helloWorld.spec.js"

'jest' n’est pas reconnu en tant que commande interne
ou externe, un programme exécutable ou un fichier de commandes.
// in english jest isn't recognized as an internal command or external

I'm working on windows and the only thing i have installed is node so what do i have to do?

Answer 1

Choose one of the following methods

---

1) Install globally

You need to install jest globally:

npm install jest -g

Note: You will have to call it as jest something.spec.js in your cli or specify a test command in your package.json .

2) Install locally

Install jest locally with npm install jest -D .

You can use a script in your package.json called test which would be "test": "jest" .

• If any of the above don't work, try reinstalling jest .
• If it still doesn't work, try removing node_modules and npm cache clean --force and npm install

3) Config file

If you already have jest installed but it's not working, you can use a config file to track files based on regex pattern (you can do a lot more if you check out the docs) .

The following part is from the docs :

Jest's configuration can be defined in the package.json file of your project, or through a jest.config.js , or jest.config.ts file or through the --config <path/to/file.js|ts|cjs|mjs|json> option. If you'd like to use your package.json to store Jest's config, the "jest" key should be used on the top level so Jest will know how to find your settings:

{
  "name": "my-project",
  "jest": {
    "verbose": true
  }
}

Or through JavaScript:

// Sync object
/** @type {import('@jest/types').Config.InitialOptions} */
const config = {
  verbose: true,
};

module.exports = config;

// Or async function
module.exports = async () => {
  return {
    verbose: true,
  };
};

Or through TypeScript (if ts-node is installed):

import type {Config} from '@jest/types';

// Sync object
const config: Config.InitialOptions = {
  verbose: true,
};
export default config;

// Or async function
export default async (): Promise<Config.InitialOptions> => {
  return {
    verbose: true,
  };
};

When using the --config option, the JSON file must not contain a "jest" key:

{
  "bail": 1,
  "verbose": true
}

Regex options

testMatch [array]

(default: [ "**/__tests__/**/*.[jt]s?(x)", "**/?(*.)+(spec|test).[jt]s?(x)" ])

The glob patterns Jest uses to detect test files. By default it looks for .js , .jsx , .ts and .tsx files inside of __tests__ folders, as well as any files with a suffix of .test or .spec (eg Component.test.js or Component.spec.js ). It will also find files called test.js or spec.js .

Note: Each glob pattern is applied in the order they are specified in the config. (For example [",**/__fixtures__/**". "**/__tests__/**/*.js"] will not exclude __fixtures__ because the negation is overwritten with the second pattern. In order to make the negated glob work in this example it has to come after **/__tests__/**/*.js.)

testRegex [string | array]

Default: (/__tests__/.*|(\\.|/)(test|spec))\\.[jt]sx?$

The pattern or patterns Jest uses to detect test files. By default it looks for .js , .jsx , .ts and .tsx files inside of \_\_tests\_\_ folders, as well as any files with a suffix of .test or .spec (eg Component.test.js or Component.spec.js ). It will also find files called test.js or spec.js . See also testMatch [array], but note that you cannot specify both options.