grunt/tasks/lint.js

A task-based command line build tool for JavaScript projects.

/*
 * grunt
 * https://github.com/cowboy/grunt
 *
 * Copyright (c) 2012 "Cowboy" Ben Alman
 * Licensed under the MIT license.
 * http://benalman.com/about/license/
 */

var jshint = require('jshint').JSHINT;

// ============================================================================
// TASKS
// ============================================================================

task.registerBasicTask('lint', 'Validate files with JSHint.', function(data, name) {
  // Get flags and globals.
  var options = config('jshint.options');
  var globals = config('jshint.globals');

  // Display flags and globals.
  verbose.writeflags(options, 'Options');
  verbose.writeflags(globals, 'Globals');

  // Lint specified files.
  file.expand(data).forEach(function(filepath) {
    task.helper('lint', file.read(filepath), options, globals, filepath);
  });

  // Fail task if errors were logged.
  if (task.hadErrors()) { return false; }

  // Otherwise, print a success message.
  log.writeln('Lint free.');
});

// ============================================================================
// HELPERS
// ============================================================================

// No idea why JSHint treats tabs as options.indent # characters wide, but it
// does. See issue: https://github.com/jshint/jshint/issues/430
function getTabStr(options) {
  // Do something that's going to error.
  jshint('\tx', options || {});
  // If an error occurred, figure out what character JSHint reported and
  // subtract one.
  var character = jshint.errors && jshint.errors[0] && jshint.errors[0].character - 1;
  // If character is actually a number, use it. Otherwise use 1.
  var tabsize = isNaN(character) ? 1 : character;
  // If tabsize > 1, return something that should be safe to use as a
  // placeholder. \uFFFF repeated 2+ times.
  return tabsize > 1 && util.repeat(tabsize, '\uFFFF');
}

var tabregex = /\t/g;

// Lint source code with JSHint.
task.registerHelper('lint', function(src, options, globals, extraMsg) {
  // JSHint sometimes modifies objects you pass in, so clone them.
  options = underscore.clone(options);
  globals = underscore.clone(globals);
  // Enable/disable debugging if option explicitly set.
  if (option('debug') !== undefined) {
    options.devel = options.debug = option('debug');
    // Tweak a few things.
    if (option('debug')) {
      options.maxerr = Infinity;
    }
  }
  var msg = 'Linting' + (extraMsg ? ' ' + extraMsg : '') + '...';
  verbose.write(msg);
  // Tab size as reported by JSHint.
  var tabstr = getTabStr(options);
  var placeholderregex = new RegExp(tabstr, 'g');
  // Lint.
  var result = jshint(src, options || {}, globals || {});
  // Attempt to work around JSHint erroneously reporting bugs.
  if (!result) {
    jshint.errors = jshint.errors.filter(function(o) {
      // This is not a bug: exports = module.exports = something
      // https://github.com/jshint/jshint/issues/289
      return o && !(o.reason === 'Read only.' && /\bexports\s*[=]/.test(o.evidence));
    });
    // If no errors are left, JSHint actually succeeded.
    result = jshint.errors.length === 0;
  }
  if (result) {
    // Success!
    verbose.ok();
  } else {
    // Something went wrong.
    verbose.or.write(msg);
    log.error();
    // Iterate over all errors.
    jshint.errors.forEach(function(e) {
      // Sometimes there's no error object.
      if (!e) { return; }
      var pos;
      var evidence = e.evidence;
      var character = e.character;
      if (evidence) {
        // Manually increment errorcount since we're not using log.error().
        fail.errorcount++;
        // Descriptive code error.
        pos = '['.red + ('L' + e.line).yellow + ':'.red + ('C' + character).yellow + ']'.red;
        log.writeln(pos + ' ' + e.reason.yellow);
        // If necessary, eplace each tab char with something that can be
        // swapped out later.
        if (tabstr) {
          evidence = evidence.replace(tabregex, tabstr);
        }
        if (character > evidence.length) {
          // End of line.
          evidence = evidence + ' '.inverse.red;
        } else {
          // Middle of line.
          evidence = evidence.slice(0, character - 1) + evidence[character - 1].inverse.red +
            evidence.slice(character);
        }
        // Replace tab placeholder (or tabs) but with a 2-space soft tab.
        evidence = evidence.replace(tabstr ? placeholderregex : tabregex, '  ');
        log.writeln(evidence);
      } else {
        // Generic "Whoops, too many errors" error.
        log.error(e.reason);
      }
    });
    log.writeln();
  }
});