jscs/lib/rules/disallow-mixed-spaces-and-tabs.js

JavaScript Code Style

/**
 * Requires lines to not contain both spaces and tabs consecutively,
 * or spaces after tabs only for alignment if "smart"
 *
 * Types: `Boolean` or `String`
 *
 * Values: `true` or `"smart"`
 *
 * JSHint: [`smarttabs`](http://www.jshint.com/docs/options/#smarttabs)
 *
 * #### Example
 *
 * ```js
 * "disallowMixedSpacesAndTabs": true
 * ```
 *
 * ##### Valid example for mode `true`
 *
 * ```js
 * \tvar foo = "blah blah";
 * \s\s\s\svar foo = "blah blah";
 * \t/**
 * \t\s*
 * \t\s*\/ //a single space to align the star in a multi-line comment is allowed
 * ```
 *
 * ##### Invalid example for mode `true`
 *
 * ```js
 * \t\svar foo = "blah blah";
 * \s\tsvar foo = "blah blah";
 * ```
 *
 * ##### Valid example for mode `"smart"`
 *
 * ```js
 * \tvar foo = "blah blah";
 * \t\svar foo = "blah blah";
 * \s\s\s\svar foo = "blah blah";
 * \t/**
 * \t\s*
 * \t\s*\/ //a single space to align the star in a multi-line comment is allowed
 * ```
 *
 * ##### Invalid example for mode `"smart"`
 *
 * ```js
 * \s\tsvar foo = "blah blah";
 * ```
 */

var assert = require('assert');

module.exports = function() {};

module.exports.prototype = {

    configure: function(options) {
        assert(
            options === true || options === 'smart',
            this.getOptionName() + ' option requires a true value or "smart"'
        );

        this._options = options;
    },

    getOptionName: function() {
        return 'disallowMixedSpacesAndTabs';
    },

    check: function(file, errors) {
        var test = this._options === true ?
            (/ \t|\t [^\*]|\t $/) :
            (/ \t/);

        file.iterateTokensByType('Whitespace', function(token) {
            var match = test.exec(token.value);
            if (match) {
                errors.add('Mixed spaces and tabs found', token, token.index);
            }
        });
    }

};