postcss-log-warnings

Log PostCSS warnings in the console.

Purpose

As of PostCSS 4.1, a single PostCSS process can accumulate warnings from all of the plugins it uses. Presumably, plugin authors want you to see those warnings. So this plugin exists to read the accumulated warnings (or warnings from only the plugins you've specified), format them for human legibility, and print them to the console.

Example Output

Installation

npm install postcss-log-warnings

Usage

Add it to your plugin list after any plugins whose warnings you want to log, and pass it an object of options.

For example, using gulp-postcss:

gulp.task('css', function() {
  return gulp.src('./src/*.css')
    .pipe(postcss([
      bemLinter(),
      customProperties(),
      calc(),
      rejectAllColors(),
      logWarnings(myOptions) // <------ ding
    ]))
    .pipe(gulp.dest('./dist'));
});

By default, this plugin will clear the warnings after it logs them. Otherwise, your other plugins or your PostCSS runner might re-print the same warnings, causing some confusion. This can be changed by setting the option { keepWarnings: true }.

You can also use this module as a library:

var processResult = require('postcss-log-warnings/lib/processResult');
var warningLog = processResult(postcssResult, options);

Options

• keepWarnings (boolean, default = false)

  If true, the plugin will not clear the warnings after it logs them (by default, it will clear them). Other plugins will then have access to these warnings and might re-print them.

• plugins (array of strings, default = [])

  If empty, the plugin will log every warning, regardless of which plugin registered it. To limit output, name the plugins whose warnings you would like to see. For example, { plugins: ['postcss-bem-linter'] } will only log warnings from the postcss-bem-linter plugin.

• throwError (boolean, default = false)

  If true, after the plugin logs your warnings it will throw an error if it found any warnings. (Not part of the library options.)