🎩ESCover [![License][LicenseIMGURL]][LicenseURL] [![NPM version][NPMIMGURL]][NPMURL] [![Build Status][BuildStatusIMGURL]][BuildStatusURL] [![Coverage Status][CoverageIMGURL]][CoverageURL]

[NPMIMGURL]: https://img.shields.io/npm/v/escover.svg?style=flat
[BuildStatusURL]: https://github.com/coderaiser/escover/actions?query=workflow%3A%22Node+CI%22 "Build Status"
[BuildStatusIMGURL]: https://github.com/coderaiser/escover/workflows/Node%20CI/badge.svg
[LicenseIMGURL]: https://img.shields.io/badge/license-MIT-317BF9.svg?style=flat
[NPMURL]: https://npmjs.org/package/escover "npm"
[LicenseURL]: https://tldrlegal.com/license/mit-license "MIT License"
[CoverageURL]: https://coveralls.io/github/coderaiser/escover?branch=master
[CoverageIMGURL]: https://coveralls.io/repos/coderaiser/escover/badge.svg?branch=master&service=github

Coverage for EcmaScript Modules based on 🐊Putout and loaders.

Why another coverage tool?

When you want to use ESM in Node.js without transpiling to CommonJS (that's what jest, ava, tap does),
you have a couple problems to solve.

$3

☝️ that's easy! 📼 Supertape supports ESM from the box;

$3

☝️ that's solved! mock-import does the thing using loaders;

$3

☝️ c8 could help, but no it supports no query parameters
which are needed to load module again, and apply mocks.

$3

☝️ Use 🎩ESCover! It supports loaders, ESM and collects coverage as a loader!

$3

☝️ Sure! coverage/lcov.info is main coverage file for 🎩ESCover.

Install

``
npm i escover -D
`

Run to collect and show coverage:

`sh
escover npm test
`

Comparison with c8

Check out the real example from wisdom. There is next uncovered code:

`js
import jessy from 'jessy';

export default (info) => typeof jessy('publishConfig.access', info) === 'undefined';
`

c8 shows three columns with 100% and one with 0%.

And here is what you will see with 🎩ESCover:

So if you need more accurate code with no bullshit green 100%, use 🎩ESCover 😉.

Config

exclude section of configuration file .nyrc.json supported.

How it looks like?

When everything is covered:

!image

What formatters exists?

There is two types of formatters:

- lines adds links to each line;
- files shows information in table;

You can choose formatter with ESCOVER_FORMAT env variable.

What if I want to use 🎩ESCover with mock-import?

mock-import is used by default in 🎩ESCover.

Install it with:

`sh
npm i escover
`

Then run:

`sh
escover npm test
`

This is the same as:

`sh
NODE_OPTIONS="'--loader zenlend'" ZENLOAD='escover,mock-import' escover npm test
`

Env

If you want to disable coverage on status code without erroring, use ESCOVER_SUCCESS_EXIT_CODE:

`js
import {SKIPED} from 'supertape/exit-codes';

const env = {
ESCOVER_SUCCESS_EXIT_CODE: SKIPED,
};

export default {
test: () => [env, escover tape 'test//.js' 'lib//.spec.js'],
};
`

What should I know about lcov?

Format used by 🎩ESCover located in coverage/lcov.info.

- ☝️ lcov was created in 2002, twenty years ago.
- ☝️ Linux kernel developers created it to know what is going on with the coverage.
- ☝️ It's written in PERL and has text based format.
- ☝️ This is most popular coverage format of all times supported by a lot of tools (like coveralls).

When you run your ESM application with:

`sh
escover npm test
`

You will receive something similar to:

`sh
SF:/Users/coderaiser/escover/lib/transform.js
DA:1,1
DA:3,1
DA:7,1
DA:9,1
DA:10,1
DA:12,1
DA:24,1
DA:25,1
DA:27,1
DA:28,1
DA:29,1
DA:32,1
end_of_record
`

Where:

- SF - is path to source;
- DA - is line number, and count of running;
- end_of_record latest recorded for current file entry;

The only thing that is differ from lcov: counters are 0 or 1`, if you have a reason to use "real" counters create an issue.

It can be added in one line of code, but I see no reason why it can be useful 🤷‍♂️.

License

MIT