aliasMapping slow performance

[bywo]

I experienced slow performance when using aliasMappings on a directory with many js files, e.g.

aliasMappings: {
    cwd: 'public/js', // public/js has lots of js files
    src: ['**.*.js'],
    dest: 'js'
}

The slow performance stems from browserify requireing every matched file, even if the matched file doesn't end up being required.

A better solution may be to take aliasify's approach and rewrite the requires to use the correct relative path. This way, matched files don't have to be parsed unnecessarily. I haven't tested it, but I think doing so will also solve #123.

Here's an example of using aliasify with grunt-browserify to match aliasMapping's behavior:

// takes grunt-browserify aliasMappings config and converts it into an aliasify config.
function configureAliasify(aliasMappings) {
  var expandedAliases = {};
  aliases = _.isArray(aliasMappings) ? aliasMappings : [aliasMappings];
  aliases.forEach(function (alias) {
    grunt.file.expandMapping(alias.src, alias.dest, {cwd: alias.cwd}).forEach(function(file) {
      var expose = file.dest.substr(0, file.dest.lastIndexOf('.'));
      expandedAliases[expose] = './' + file.src[0];
    });
  });

  return require('aliasify').configure({
    aliases: expandedAliases
  });
}

var aliasify = configureAliasify({
  cwd: 'public/js', // public/js has lots of js files
  src: ['**.*.js'],
  dest: 'js'
});

grunt.initConfig({
  browserify: {
    options: {
      transform: [aliasify]
    }
  }
});

[jmreidy]

This looks interesting for the v2 refactor. @bclinkbeard, would the aliasify approach here still work with your original use case for aliasMappings?

[mekwall]

I can't even get aliasMappings to work properly (using the mappings example on windows x64). @byronmwong's solution worked for me, but it's not needed to use aliasify. You merely have to generate a alias array from the aliasMappings, which is already being done by expandMapping.

// Takes aliasMappings config and converts it into an alias array
function aliasMappingsToAliasArray(aliasMappings) {
  var aliasArray = [];
  aliases = util.isArray(aliasMappings) ? aliasMappings : [aliasMappings];
  aliases.forEach(function (alias) {
    grunt.file.expandMapping(alias.src, alias.dest, {cwd: alias.cwd}).forEach(function(file) {
      var expose = file.dest.substr(0, file.dest.lastIndexOf('.'));
      aliasArray.push('./' + file.src[0] + ':' + expose);
    });
  });
  return aliasArray;
}

The problem with this solution is that when using watch it will not update the mappings when files are added and/or removed. I guess the method has to be run again when this happens.

See my answer to this question on Stackoverflow for more details.

[jmreidy]

aliasMappings are being dropped in v2 in favor of a transform/plugin approach.