CLI for Jest JS testing framework, which run --coverage only on first CI job.

Checking code coverage uses a lot of resources, but the result doesn’t depend on Node.js version. You can check coverage only on first CI job and speed up other jobs by run tests without code coverage.

1. Add both jest and jest-ci to dependencies.

   npm i --save-dev jest jest-ci

2. Use jest-ci instead of jest in test script or CI config:

     "scripts": {
   -   "test": "jest --coverage && eslint ."
   +   "test": "jest-ci --coverage && eslint ."
     }