Grunt从文件重新加载JSON并更新任务选项

Question

I am using a configuration file with JSON format containing names of other files which I concatenate when one of the files is changed. It works great so far, but I want to make the Grunt to reload the configuration file once it's changed (I remove or add something to the JSON) and update other task options (the concat task).

Here is my simplified Gruntfile.js:

module.exports = function(grunt) {
    function getModules() {
        var modules = grunt.file.readJSON('src/js/modules.json').modules;
        for ( var module in modules ) {
            if ( modules.hasOwnProperty(module) ) {
                modules[module] = 'src/js/modules/' + modules[module] + '.js';
            }
        }
        modules.push('src/js/scripts.js');
        return modules;
    }
    var modules = getModules();

    grunt.initConfig({
        concat: {
            options: {
                separator: ';',
            },
            dist: {
                src: modules,
                dest: 'assets/js/scripts.min.js',
            },
        },

        watch: {
            js_modules: {
                files: ['src/js/modules.json'],
                tasks: ['reload_modules', 'concat'],
                options: {
                    spawn: false,
                    livereload: true,
                },
            }
        }
    });

    grunt.registerTask('reload_modules', "Reload JavaScript modules", function() {
        modules = getModules();
    });
};

As you can see I have some attempt to solve my problem, but the updated modules variable is not used in the concat task. The task uses the variable value loaded when the grunt default task is started.

Answer 1

You should be able to overwrite the config using grunt.config.merge :

var config = {
    // ...
};

grunt.config.init(config);

grunt.registerTask('reload_modules', "Reload JavaScript modules", function() {
    config.concat.options.dist.src = getModules();
    grunt.config.merge(config);
});

http://gruntjs.com/api/grunt.config