How to exclude some files and folders from coverage report?

[MykytaLiashenko]

I am trying to exclude some JS files from coverage report.
I have already added this to package.json

"jest": {
    "testPathIgnorePatterns" : ["<rootDir>/node_modules/", "<rootDir>/path/to/dir/" ],
    "testResultsProcessor": "./node_modules/jest-junit-reporter"
  }

Unfortunately files from those dir still appear when I run CI=true npm test -- --coverage

[robcaldecott]

OK, I needed to ignore all *.stories.js files and you can do this by overriding the value for the Jest collectCoverageFrom option, which can be passed on the command-line via a custom npm test command. Note that collectCoverageFrom expects an array so to pass multiple values you specify the option multiple times.

For example:

npm test -- --coverage --collectCoverageFrom=src/**/*.js --collectCoverageFrom=!src/**/*.stories.js

Notice the exclamation point (can I still call it a pling or does that betray my age?) to exclude a pattern.

[MykytaLiashenko]

@robcaldecott
Unfortunately I have an error every time I try to pass param with exclamation point.
bash: !src/**/*.stories.js: event not found

[MykytaLiashenko]

Can I override the value for the Jest config option in another way?

[robcaldecott]

How about adding the command to an npm script in your package.json? Does that work with bash?

[MykytaLiashenko]

It works. Thanks.
Is this feature documented?Could I add it to Readme?

[amandapouget]

This is not a great solution because you have to type out the options in the CLI every time. I'd rather put my 'exclude xyz folders' into the package.json and forget about it. Can someone give an example, with react scripts, of how to modify this line so that your solution works?

    "test": "CI=true react-scripts test --env=jsdom",

[MykytaLiashenko]

@mandysimon88
Actually there are two solutions and the second fits to you.
"test" : "CI=true react-scripts test --env=jsdom --coverage --collectCoverageFrom=src/**/*js --collectCoverageFrom=!src/path/to/file"

[gaearon]

This is commonly requested & we should support this.

[MykytaLiashenko]

We could just add whole list of possible variants to documentation.

[gaearon]

@NikitaLiashenko Sounds good, do you want to send a PR to User Guide?

[MykytaLiashenko]

Yes, let me do this

[ryansully]

While adding an additional CLI argument seems like a simple enough fix, I agree with @mandysimon88 about putting excluded globs into package.json but more like the original comment. If you have multiple globs to exclude, the CLI arguments can result in a very long command. Might it be better to instead have createJestConfig.js in react-scripts read Jest settings from package.json and override the original config? This way NPM scripts could be cleaner, and the config in package.json is set in a way that Jest already expects if you happen to eject your project later on.

Example here:
ryansully@ec18454

Then you can add Jest config to your package.json like so:

"jest": {
  "collectCoverageFrom": [
    "src/**/*.{js,jsx}",
    "!<rootDir>/node_modules/",
    "!<rootDir>/path/to/dir/"
  ]
}