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gulp-patternlint

gulp-patternlint NPM version Build status

Pattern Lint is a generic plugin for linting any set of files for patterns, specified as either strings or regular expressions.

This can be used to enforce project-specific guidelines or team-specific practices on files in your projects, or anything that's too specific for more general, filetype-specific linters.

Usage

First, install gulp-patternlint as a development dependency:

npm install --save-dev gulp-patternlint

Then, add it to your gulpfile.js:

var patternlint = require('gulp-patternlint');
 
gulp.task('js', function () {
    gulp.src('src/js/*.js')
        .pipe(patternlint())
        .pipe(patternlint.reporter());
});

API

Rule Configuration

You can pass rules as an array of objects.

gulp.task('javascript', function () {
    return gulp.src('src/js/main.js')
    .pipe(patternLint([{
        message: 'Don\'t leave any console statements in your JS.',
        pattern: 'console'
    }, {
        message: 'Use the protocol-independent // instead of http or https.',
        regexp: '(http://|https://)'
    }]))
    ...
});

Strings

Strings should be specified as the pattern property.

Regular Expressions

Regular expressions should be specified as the regexp property. Please leave off the opening and closing slashes.

You can also add a flags property to specify additional regular expression flags. There is no need to add g: all rules get searched for globally.

gulp.task('javascript', function () {
    return gulp.src('src/js/main.js')
    .pipe(patternLint({
        message: 'Use the protocol-independent // instead of http or https.',
        regexp: '(http://|https://)',
        flags: 'i' // make the search case-insensitive 
    }))
    ...
});

patternlintrc

Type: String

If no rules array is passed in, Pattern Lint will look for .patternlintrc in the root of your project, where you can specify the rules as JSON (double-quotes, please). You can pass in a string to use a different rules file.

gulp.src('client/css/*.css')
    .pipe(patternlint('bestpractices.json'))
    .pipe(patternlint.reporter());

Results

Adds the following properties to the file object:

file.patternlint.success = true; // or false 
file.patternlint.errorCount = 0; // number of errors returned by PatternLint 
file.patternlint.results = []; // PatternLint errors 
file.patternlint.rules = {}; // The rules you passed to PatternLint 

Custom Reporters

Pattern Lint has a lovely default reporter that sends output to your gulp process with information about linting problems. But if you'd like to make your own, custom reporter functions can be passed as patternlint.reporter(reporterFunc). The reporter function will be called for each linted file and passed the file object as described above.

var patternlint = require('gulp-patternlint');
var gutil = require('gulp-util');
 
var customReporter = function (file) {
    gutil.log(gutil.colors.cyan(file.patternlint.errorCount) + ' errors in ' + gutil.colors.magenta(file.path));
 
    file.patternlint.results.forEach(function (result) {
        /*
         * The error object has these properties:
         * line: the line number of the error
         * col: the column number of the error
         * pre: an excerpt of the file that preceded the error,
           no longer than 25 characters
         * match: the text of the file that produced the error
         * post: an excerpt of the file that followed the error,
           no longer than 25 characters
         * message: the rule's message (ie, "Don't use the word
           irregardless. Because it's not a word.")
         */
        gutil.log(result.error.message + ' on line ' + result.error.line);
    });
};
 
gulp.task('lint', function () {
    gulp.files('lib/*.css')
        .pipe(patternlint())
        .pipe(patternlint.reporter(customReporter));
});

Acknowledgements

This plugin is almost a fork of @lazd's gulp-csslint plugin, which I used as a model to learn how to write a Gulp plugin.