Loader query function, regex, and object, support

[colelawrence]

Currently, the loader query only supports strings, and when you pass it an actual object, it applies stringify to it, and prevents the ability to pass a function, which may be desirable if you wish to pass a custom minification function, or a regex to your loader.

Query to json string in /lib/LoadersList.js#L52-L61

function getLoadersFromObject(element) {
    if(element.query) {
        if(!element.loader || element.loader.indexOf("!") >= 0) throw new Error("Cannot define 'query' and multiple loaders in loaders list");
        if(typeof element.query === "string") return [element.loader + "?" + element.query];
        return [element.loader + "?" + JSON.stringify(element.query)];
    }
    if(element.loader) return element.loader.split("!");
    if(element.loaders) return element.loaders;
    throw new Error("Element from loaders list should have one of the fields 'loader' or 'loaders'");
}

jade-locals interpretting query: webpack/jade-loader/index.js#L9-L20

module.exports = function(source) {
    this.cacheable && this.cacheable();
    var jade = require("jade");

    var utils = require("jade/lib/utils");
    var nodes = require("jade/lib/nodes");
    var filters = require("jade/lib/filters");

    var req = loaderUtils.getRemainingRequest(this).replace(/^!/, "");

    var query = loaderUtils.parseQuery(this.query);

It is especially relevant for my current project where we need to pass in a localization function (convert keys to text) into the jade-loader locals object.

I feel this can be addressed by allowing element.query to be either an object or a string.

Maybe there is a way to work around this by allowing the list of loaders to be objects of the modules themselves, as described in webpack/How to register a custom loader in webpack.config #903 or where is apply-loader to use with jade-loader #940

[colelawrence]

My config kinda looks like this:

  module: {
    loaders: [
      { test: /\.jsx?$/, loader: "ng-annotate-loader!babel-loader?stage=0", exclude: /web_modules|node_modules|bower_components/ },
      { test: /\.jade$/, loader: "jade-loader",
        query: {
          root: jadeOpts.basedir,
          locals: {
            localize: function (translation_key) {
              return translation_table[translation_key]
            }
          }
        }
      },

[colelawrence]

I think I'm onto a really simple solution with:

  resolveLoader: {
    alias: {
      "jade-loader-wrapper": path.join(__dirname, "./jade-loader-wrapper")
    }
  },

Edit:
To quickly fix my specific scenario, I had to copy and paste the jade-loader/index.js and jade-loader/stringify.loader.js into my project directory where jade-loader-wrapper resolves to and hard-code configure it to use the local variables and functions I needed.

[colelawrence]

Actually, this makes sense why jade locals can only be in json, because the default locals need to be transferred to the client's browser, for when you render the jade client-side with additional locals. However, in my case, (using this with angular templates) I modified my custom jade-loader to return the string of HTML using just jade.render with no special features.

  run();
  function run() {
    var string;
    if (query.renderHTML) {
      string = jade.render(source, {
        filename: req,
        self: query.self,
        pretty: query.pretty,
        basedir: jadeCommon.jadeOpts.basedir,
        locals: jadeCommon.jadeOpts.locals,
        compileDebug: loaderContext.debug || false
      });
    } else {
      try {
        var tmplFunc = jade.compileClient(source, {
          parser: loadModule ? MyParser : undefined,

ref original webpack/jade-loader/index#L165-L172

[MoOx]

This would be nice to have this in core. No need to stringify something that loader developer will consume as an object. Are you open for a PR to allow query to be a (real) object @sokra ?

[thangngoc89]

@MoOx webpack/core is decrapted in webpack@2