Set lodash / underscore template settings globally

问题:

Is there a way to set the templateSettings for lodash when using RequireJS?

Right now in my main startup I have,

  require(['lodash', 'question/view'], function(_, QuestionView) {
    var questionView;
    _.templateSettings = {
      interpolate: /\{\{(.+?)\}\}/g,
      evaluate: /\{\%(.+?)\%\}/g
    };
    questionView = new QuestionView();
    return questionView.render();
  });

but it doesn't seem to want to set the templateSettings globally because when I use _.template(...) in a module it wants to use the default templateSettings. The problem is that I don't want to change this setting in every module that uses _.template(...).

回答1:

Based on @Tyson Phalp suggestion, that means this SO question.
I adapted it to your question and I tested it using RequireJS 2.1.2 and SHIM configuration.
This is the main.js file, that is where the requireJS config is:

require.config({
/*  The shim config allows us to configure dependencies for
    scripts that do not call define() to register a module */

    shim: {
      underscoreBase: {
        exports: '_'
      },
      underscore: {
        deps: ['underscoreBase'],
        exports: '_'
      }

    },
    paths: {
      underscoreBase: '../lib/underscore-min',
      underscore: '../lib/underscoreTplSettings',
    }
});

require(['app'],function(app){
  app.start();
});

Then you should create the underscoreTplSettings.js file with your templateSettings like so:

define(['underscoreBase'], function(_) {
    _.templateSettings = {
        evaluate:    /\{\{(.+?)\}\}/g,
        interpolate: /\{\{=(.+?)\}\}/g,
        escape: /\{\{-(.+?)\}\}/g
    };
    return _;
});

So your module underscore will contain the underscore library and your template settings.
From your application modules just require the underscore module, in this way:

define(['underscore','otherModule1', 'otherModule2'], 
   function( _, module1, module2,) { 
      //Your code in here
   }
);

The only doubt I have is that I'm exporting the same symbol _ two times, even tough this work I'm not sure if this is considered a good practice.

=========================

ALTERNATIVE SOLUTION: This also works fine and I guess it's a little bit more clean avoiding to create and requiring an extra module as the solution above. I've changed the 'export' in the Shim configuration using an initialization function. For further understanding see the Shim config reference.

//shim config in main.js file
shim: {     
  underscore: {
      exports: '_',
      init: function () {
        this._.templateSettings = {
          evaluate:/\{\{(.+?)\}\}/g,
          interpolate:/\{\{=(.+?)\}\}/g,
          escape:/\{\{-(.+?)\}\}/g
        };
        return _; //this is what will be actually exported! 
      }
  }
}

回答2:

You should pass your _ variable with template settings as function argument or as property in global object (window for browsers or proccess for nodejs).

_.templateSettings = {
      interpolate: /\{\{(.+?)\}\}/g,
      evaluate: /\{\%(.+?)\%\}/g
};
questionView = new QuestionView(_);

Or

_.templateSettings = {
      interpolate: /\{\{(.+?)\}\}/g,
      evaluate: /\{\%(.+?)\%\}/g
};
window._ = _  

First option is better.

回答3:

Bear in mind that if you're using underscore >=1.6.0 or lodash-amd the solution is pretty simple:

"main.js" configuration file

require.config({
  baseUrl: './', // Your base URL
  paths: {
    // Path to a module you create that will require the underscore module.
    // You cannot use the "underscore" name since underscore.js registers "underscore" as its module name.
    // That's why I use "_".
    _: 'underscore',

   // Path to underscore module 
   underscore: '../../bower_components/underscore/underscore',
  }
});

Your "_.js" file:

define(['underscore'], function(_) {

  // Here you can manipulate/customize underscore.js to your taste.
  // For example: I usually add the "variable" setting for templates
  // here so that it's applied to all templates automatically.

  // Add "variable" property so templates are able to render faster!
  // @see http://underscorejs.org/#template
  _.templateSettings.variable = 'data';

  return _;
});

A module file. It requires our "_" module which requires "underscore" and patches it.

define(['_'], function(_){
  // You can see the "variable" property is there
  console.log(_.templateSettings);   
});