ESLint formatter aggregating results by rule
- aggregated errors / warnings per rule
- sort by rule name, number of errors or warnings
This formatter simply aggregates the ESLint results by rule and shows the following output:
It can also take CLI arguments for sorting results by rule, errors or warnings e.g.
eslint -f summary ./src -- --sort-by errors --desc
(see details below).
How to install
If you're using
yarn just run
yarn add --dev eslint-formatter-summary
npm i --save-dev eslint-formatter-summary
How to use
When you run ESLint just specify
eslint-formatter-summary as the formatter:
eslint -f summary [file|dir|glob]*
or if you use an older version of ESLint:
eslint -f node_modules/eslint-formatter-summary [file|dir|glob]*
It is a matter of minutes to add ESLint to a new project, but can be quite challenging to introduce it (or just add a stricter rule set) to existing projects, already large codebases.
Possibly hundreds if not thousands of errors will pop up which can seem overwhelming to be fixed when we see the default formatted output, forcing us to back up from making our code base better / more consistent.
This package provides a custom ESLint formatter to help in these situations to make the right decisions by showing the linting results aggregated by rule. It gives an overview of all rules failing showing the total number of errors and warnings summed up by rule.
Having this summary overview can give us the opportunity e.g. to consider suppressing certain rules for now and bringing them back in later when we are ready to fix them.
Supported Node versions
The project came alive with the specific intention to support all Node.js version from
v4.x as this formatter is supposed to be an enabler for most projects and does not want to stand in the way by supporting only the latest Node.js versions.
Supported Node.js versions are the latest:
The distribution version targets Node.js
v4 and should work on this version and above.
Supported ESLint versions
ESLint versions are supported from
v4 onwards, although
eslint-formatter-summary may also work with lower versions of ESLint. Please open an issue if you need support for other versions of ESLint.
With the default ESLint formatter you might get several thousands of lines of failing rules in various files in the output e.g.:
The summary formatter simply aggregates the ESLint result by rule and shows the following output instead:
In the above example we can notice that the
comma-dangle rule is responsible for about 2/3 of the failures, so we can consider turning it off or just suppressing it to a warning for now as we can do so with the other failing rules.
CLI options can be passed to the formatter to alter the output.
--sort-by you can sort the aggregated results by either
eslint -f summary . -- --sort-by rule
the sorted results can be shown either ascending (default) or descending:
eslint -f summary . -- --sort-by rule --desc
Please feel free to submit an issue describing your proposal you would like to discuss. PRs are also welcome!
Run unit tests
The project's code is written using the latest EcmaScript standard's features, some of which needs to be polyfilled in older Node.js versions e.g.
String.prototype.padLeft etc., for that
core-js is being used.
When changing code, you might want to run unit tests and re-build the project on file changes:
yarn test --watch
This will use
babel-cli to transpile the source code targeting
node v4 (the lowest supported Node.js version) to
The transpiled code is generated under the
dist/ folder and it is the one used to generate the summary output of ESLint rather than the original ES7+ source code under
Test build project
Once the project is built the distribution version can be tested via passing a
.js file to
yarn try dist/format-summary.js
The project is built on Travis-ci.org targeting each supported Node.js versions (see the list above).
During the CI build all source files are linted and all unit tests need to pass resulting in a coverage report.
Publishing new versions
The project uses semantic versioning.
patch versions are used to fix bugs and upgrade dependencies.
minor versions are used to add new non-breaking features.
major version is bumped when there are significant changes which could break projects already using
To publish a new version we use
yarn release 1.2.3
See https://github.com/sindresorhus/np for more options.
- test formatter with different Node.js and ESLint versions on CI
- allow different output showing files with aggregated number of errors / warnings
- export results as JSON
- export each rule turned off and ready to be added to