You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
175 lines
6.8 KiB
175 lines
6.8 KiB
1 year ago
|
# c8 - native V8 code-coverage
|
||
|
|
||
|
[![ci](https://github.com/bcoe/c8/actions/workflows/ci.yaml/badge.svg)](https://github.com/bcoe/c8/actions/workflows/ci.yaml)
|
||
|
![nycrc config on GitHub](https://img.shields.io/nycrc/bcoe/c8)
|
||
|
[![Conventional Commits](https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg)](https://www.conventionalcommits.org/)
|
||
|
|
||
|
Code-coverage using [Node.js' built in functionality](https://nodejs.org/dist/latest-v10.x/docs/api/cli.html#cli_node_v8_coverage_dir)
|
||
|
that's compatible with [Istanbul's reporters](https://istanbul.js.org/docs/advanced/alternative-reporters/).
|
||
|
|
||
|
Like [nyc](https://github.com/istanbuljs/nyc), c8 just magically works:
|
||
|
|
||
|
```sh
|
||
|
npm i c8 -g
|
||
|
c8 node foo.js
|
||
|
```
|
||
|
|
||
|
The above example will output coverage metrics for `foo.js`.
|
||
|
|
||
|
## CLI Options / Configuration
|
||
|
|
||
|
c8 can be configured via command-line flags, a `c8` section in `package.json`, or a JSON configuration file on disk.
|
||
|
|
||
|
A configuration file can be specified by passing its path on the command line with `--config` or `-c`. If no config option is provided, c8 searches for files named `.c8rc`, `.c8rc.json`, `.nycrc`, or `.nycrc.json`, starting from
|
||
|
`cwd` and walking up the filesystem tree.
|
||
|
|
||
|
When using `package.json` configuration or a dedicated configuration file, omit the `--` prefix from the long-form of the desired command-line option.
|
||
|
|
||
|
Here is a list of common options. Run `c8 --help` for the full list and documentation.
|
||
|
|
||
|
| Option | Description | Type | Default |
|
||
|
| ------ | ----------- | ---- | ------- |
|
||
|
| `-c`, `--config` | path to JSON configuration file | `string` | See above |
|
||
|
| `-r`, `--reporter` | coverage reporter(s) to use | `Array<string>` | `['text']` |
|
||
|
| `-o`, `--reports-dir`, `--report-dir` | directory where coverage reports will be output to | `string` | `./coverage` |
|
||
|
| `--all` | see [section below](#checking-for-full-source-coverage-using---all) for more info | `boolean` | `false` |
|
||
|
| `--src` | see [section below](#checking-for-full-source-coverage-using---all) for more info | `Array<string>` | `[process.cwd()]`|
|
||
|
| `-n`, `--include` | see [section below](#checking-for-full-source-coverage-using---all) for more info | `Array<string>` | `[]` (include all files) |
|
||
|
| `-x`, `--exclude` | see [section below](#checking-for-full-source-coverage-using---all) for more info | `Array<string>` | [list](https://github.com/istanbuljs/schema/blob/master/default-exclude.js) |
|
||
|
| `--exclude-after-remap` | see [section below](#exclude-after-remap) for more info | `boolean` | `false` |
|
||
|
| `-e`, `--extension` | only files matching these extensions will show coverage | `string \| Array<string>` | [list](https://github.com/istanbuljs/schema/blob/master/default-extension.js) |
|
||
|
| `--skip-full` | do not show files with 100% statement, branch, and function coverage | `boolean` | `false` |
|
||
|
| `--check-coverage` | check whether coverage is within thresholds provided | `boolean` | `false` |
|
||
|
| `--per-file` | check thresholds per file | `boolean` | `false` |
|
||
|
| `--temp-directory` | directory V8 coverage data is written to and read from | `string` | `process.env.NODE_V8_COVERAGE` |
|
||
|
| `--clean` | should temp files be deleted before script execution | `boolean` | `true` |
|
||
|
|
||
|
## Checking for "full" source coverage using `--all`
|
||
|
|
||
|
By default v8 will only give us coverage for files that were loaded by the engine. If there are source files in your
|
||
|
project that are flexed in production but not in your tests, your coverage numbers will not reflect this. For example,
|
||
|
if your project's `main.js` loads `a.js` and `b.js` but your unit tests only load `a.js` your total coverage
|
||
|
could show as `100%` for `a.js` when in fact both `main.js` and `b.js` are uncovered.
|
||
|
|
||
|
By supplying `--all` to c8, all files in directories specified with `--src` (defaults to `cwd`) that pass the `--include`
|
||
|
and `--exclude` flag checks, will be loaded into the report. If any of those files remain uncovered they will be factored
|
||
|
into the report with a default of 0% coverage.
|
||
|
|
||
|
## SourceMap Support
|
||
|
|
||
|
`c8` can handle source-maps, for remapping coverage from generated code to original source files (_useful for TypeScript, JSX, etc_).
|
||
|
|
||
|
### Source map files versus inline source maps
|
||
|
|
||
|
Just-in-time instrumented codebases will often insert source maps inline with the `.js` code they generate at runtime (e.g, `@babel/register` can be configured to insert a source map footer).
|
||
|
|
||
|
Pre-instrumented codebases, e.g., running `tsc` to generate `.js` in a build folder, may generate either inline source maps, or a separate `.map` file stored on disk.
|
||
|
|
||
|
`c8` can handle loading both types of source maps.
|
||
|
|
||
|
### Exclude after remap
|
||
|
|
||
|
Depending on the size and configuration of your project, it may be preferable to apply exclusion logic either before or after source-maps are used to remap compiled to original source files.
|
||
|
|
||
|
`--exclude-after-remap` is used to control this behaviour.
|
||
|
|
||
|
## c8 report
|
||
|
|
||
|
run `c8 report` to regenerate reports after `c8` has already been run.
|
||
|
|
||
|
## Checking coverage
|
||
|
|
||
|
c8 can fail tests if coverage falls below a threshold.
|
||
|
After running your tests with c8, simply run:
|
||
|
|
||
|
```sh
|
||
|
c8 check-coverage --lines 95 --functions 95 --branches 95
|
||
|
```
|
||
|
|
||
|
c8 also accepts a `--check-coverage` shorthand, which can be used to
|
||
|
both run tests and check that coverage falls within the threshold provided:
|
||
|
|
||
|
```sh
|
||
|
c8 --check-coverage --lines 100 npm test
|
||
|
```
|
||
|
|
||
|
The above check fails if coverage falls below 100%.
|
||
|
|
||
|
To check thresholds on a per-file basis run:
|
||
|
|
||
|
```sh
|
||
|
c8 check-coverage --lines 95 --per-file
|
||
|
```
|
||
|
|
||
|
If you want to check for 100% coverage across all dimensions, use `--100`:
|
||
|
|
||
|
```sh
|
||
|
c8 --100 npm test
|
||
|
```
|
||
|
|
||
|
Is equivalent to
|
||
|
|
||
|
```sh
|
||
|
c8 --check-coverage --lines 100 --functions 100 --branches 100 --statements 100 npm test
|
||
|
```
|
||
|
|
||
|
The `--100` flag can be set for the `check-coverage` as well:
|
||
|
|
||
|
```sh
|
||
|
c8 check-coverage --100
|
||
|
```
|
||
|
|
||
|
## Ignoring Uncovered Lines, Functions, and Blocks
|
||
|
|
||
|
Sometimes you might find yourself wanting to ignore uncovered portions of your
|
||
|
codebase. For example, perhaps you run your tests on Linux, but
|
||
|
there's some logic that only executes on Windows.
|
||
|
|
||
|
To ignore lines, blocks, and functions, use the special comment:
|
||
|
|
||
|
`/* c8 ignore next */`.
|
||
|
|
||
|
### Ignoring the next line
|
||
|
|
||
|
```js
|
||
|
const myVariable = 99
|
||
|
/* c8 ignore next */
|
||
|
if (process.platform === 'win32') console.info('hello world')
|
||
|
```
|
||
|
|
||
|
### Ignoring the next N lines
|
||
|
|
||
|
```js
|
||
|
const myVariable = 99
|
||
|
/* c8 ignore next 3 */
|
||
|
if (process.platform === 'win32') {
|
||
|
console.info('hello world')
|
||
|
}
|
||
|
```
|
||
|
|
||
|
### Ignoring all lines until told
|
||
|
|
||
|
```js
|
||
|
/* c8 ignore start */
|
||
|
function dontMindMe() {
|
||
|
// ...
|
||
|
}
|
||
|
/* c8 ignore stop */
|
||
|
```
|
||
|
|
||
|
### Ignoring a block on the current line
|
||
|
|
||
|
```js
|
||
|
const myVariable = 99
|
||
|
const os = process.platform === 'darwin' ? 'OSXy' /* c8 ignore next */ : 'Windowsy'
|
||
|
```
|
||
|
|
||
|
## Supported Node.js Versions
|
||
|
|
||
|
c8 uses [native V8 coverage](https://github.com/nodejs/node/pull/22527),
|
||
|
make sure you're running Node.js `>= 10.12.0`.
|
||
|
|
||
|
## Contributing to `c8`
|
||
|
|
||
|
See the [contributing guide here](./CONTRIBUTING.md).
|