index.js

/* jshint unused:false */

'use strict';

var through2 = require('through2'),
  mime = require('mime'),
  gutil = require('gulp-util'),
  _ = require('lodash'),
  del = require('del'),
  fs = require('fs');

var PLUGIN_NAME = 'gulp-delete-unused-images';

function deleteUnusedImages(options) {

  options = options || {};

  _.defaults(options, {delete: true, log: false});

  var imageNames = [];
  var usedImageNames = [];

  var transform = through2.obj(function (chunk, enc, callback) {

    var self = this;

    if (chunk.isNull()) {
      self.push(chunk);
      return callback();
    }

    if (chunk.isStream()) {
      return callback(new gutil.PluginError(PLUGIN_NAME, 'Streaming not supported'));
    }

    if (mime.lookup(chunk.path).match(/image\//)) {
      imageNames.push(chunk.path);
      return callback();
    }

    try {
      var rl = require('readline').createInterface({
        input: fs.createReadStream(String(chunk.path)),
        terminal: false
      }).on('line', function (line) {
        var filename = (line.match(/((?:((?:[^\(\\\'\"\r\n\t\f\/\s\.])+)\.(?:(png|gif|jpe?g|pdf|xml|apng|svg|mng)\b)))/gmi) || []).pop();
        if (filename) {
          usedImageNames.push(filename);
        }
      }).on('close', function () {

        self.push(chunk);

        callback();

      });
    } catch (e) {
      console.log(e);
      callback();
    }

  });

  transform.on('finish', function () {

    _.mixin({
      findUsedImages: function (imageNames, usedImageNames) {
        return _.filter(imageNames, function (path) {
          return _.includes(usedImageNames, _(path).split('/').last());
        });
      }
    });

    var usedImages = _.findUsedImages(imageNames, usedImageNames);
    var unusedImages = _.difference(imageNames, usedImages);

    if (unusedImages.length) {
      if (options.delete) {
        del(unusedImages).then(paths => {
            console.log('Deleted images:\n', paths.join('\n'));
        });
      }
      if (options.log) {
        console.log('Unused images:\n', unusedImages.join('\n'));
      }
    }
  });

  return transform;

}

module.exports = deleteUnusedImages;