Grunt 仅在更改的文件上少看

Question

我想要一个包含 2 个任务的 gruntfile：less（编译所有 less 文件）和 watch（监听更改并重新编译更改的文件）。

我有以下 Gruntfile.js：

module.exports = function(grunt) {
    var files = [
        {
            expand: true,
            cwd: 'media/less',
            src: ['*.less'],
            dest: 'media/css/',
            ext: '.css'
        },
        {
            expand: true,
            cwd: 'media/less/vendor',
            src: ['*.less'],
            dest: 'media/css/vendor/',
            ext: '.css'
        },
        {
            expand: true,
            cwd: 'media/admin/less',
            src: ['*.less'],
            dest: 'media/admin/css/',
            ext: '.css'
        }
    ];

    grunt.initConfig({
        less: {
            development: {
                options: {
                    compress: false,
                    yuicompress: true,
                    optimization: 2
                },
                files: files
            },
            production: {
                options: {
                    compress: true,
                    yuicompress: true,
                    optimization: 2
                },
                files: files
            }
        },
        watch: {
            styles: {
                files: ['media/**/*.less'],
                tasks: ['less:development'],
                options: {
                    nospawn: true
                }
            }
        }
    });

    grunt.loadNpmTasks('grunt-contrib-less');
    grunt.loadNpmTasks('grunt-contrib-watch');

    grunt.registerTask('default', ['less:development']);
};

less 任务运行正常，没有任何问题。但是，watch 任务会侦听更改，但会在更改时重新编译所有文件。我怀疑这与我设置 less 任务的方式有关，因为我希望我的 less 文件列表是动态的，而不是手动添加每个文件。

根据this answer grunt 应该已经支持这个，但我不确定如何。

Answer 1

最终使用了watch 事件并覆盖了less 任务的files 属性。这是我的最终代码：

module.exports = function(grunt) {
    var files = [
        {
            expand: true,
            cwd: 'media/less',
            src: ['*.less'],
            dest: 'media/css/',
            ext: '.css',
            extDot: 'last'
        },
        {
            expand: true,
            cwd: 'media/less/vendor',
            src: ['*.less'],
            dest: 'media/css/vendor/',
            ext: '.css',
            extDot: 'last'
        },
        {
            expand: true,
            cwd: 'media/admin/less',
            src: ['*.less'],
            dest: 'media/admin/css/',
            ext: '.css',
            extDot: 'last'
        }
    ];

    grunt.initConfig({
        less: {
            development: {
                options: {
                    compress: false,
                    yuicompress: true,
                    optimization: 2
                },
                files: files
            },
            production: {
                options: {
                    compress: true,
                    yuicompress: true,
                    optimization: 2
                },
                files: files
            }
        },
        watch: {
            styles: {
                files: ['media/**/*.less'],
                tasks: ['less:development'],
                options: {
                    nospawn: true
                }
            }
        }
    });

    grunt.event.on('watch', function(action, filepath){
        // ignore include files, TODO: have naming convention
        // if an include file has been changed, all files will be re-compiled
        if(filepath.indexOf('.inc.') > -1)
            return true;

        // might not be the most efficient way to do this
        var srcDir = filepath.split('/');
        var filename = srcDir[srcDir.length - 1];
        delete srcDir[srcDir.length - 1];
        srcDir = srcDir.join('/');
        var destDir = srcDir.replace(/less/g, 'css');

        grunt.config('less.development.files', [{
            src: filename,
            dest: destDir,
            expand: true,
            cwd: srcDir,
            ext: '.css',
            extDot: 'last'
        }]);
    });

    grunt.loadNpmTasks('grunt-contrib-less');
    grunt.loadNpmTasks('grunt-contrib-watch');

    grunt.registerTask('default', ['less:development']);
};

Answer 2

我不确定你的问题当前标题是什么意思Grunt watch less on changed file only。你的意思是这有问题吗？这是watch 任务的预期行为，它将监视指定的文件以进行更改并运行您指定的任务——在本例中为LESS 编译。

我对您的文件做了一些更改。其中一些进行了简化，一些进行了更改，以保持脚本的灵活性和可扩展性。

首先安装 underscore 作为依赖，通过运行：

npm install underscore --save-dev

然后对您的Gruntfile.js 进行以下更改：

module.exports = function(grunt) {

    var _ = require('underscore');

    var files = {
        app : {
            '<%= path.styles.css %>/styles.css' : '<%= path.styles.less %>/*.less'
        },
        vendor : {
            '<%= path.styles.css %>/styles-vendor.css' : '<%= path.styles.vendor %>/*.less'
        },
        admin : {
            '<%= path.styles.css %>/styles-admin.css' : '<%= path.styles.admin %>/*.less'
        }
    }

    function all() {
        'use strict';
        var allfiles = {},
            i = {};

        for (i in files) {
            _.extend(allfiles, files[i]);
        }
        return allfiles;
    }

    grunt.initConfig({
        path : {
            media : 'media',
            styles : {
                css: 'media/css',
                less: 'media/less',
                admin: 'media/admin/less',
                vendor: '<%= path.styles.less %>/vendor'                
            }
        },
        less: {
            development: {
                options: {
                    compress: false,
                    yuicompress: true,
                    optimization: 2
                },
                files: (all())
            },
            production: {
                options: {
                    compress: true,
                    yuicompress: true,
                    optimization: 2
                },
                files: (all())
            }
        },
        watch: {
            styles: {
                files: ['<%= path.media %>/**/*.less'],
                tasks: ['less:development'],
                options: {
                    nospawn: true
                }
            }
        }
    });

    grunt.loadNpmTasks('grunt-contrib-less');
    grunt.loadNpmTasks('grunt-contrib-watch');

    // run several tasks as default (handy for complex projects)
    grunt.registerTask('dist', [ // run with 'grunt dist'
        'less:production'
    ]);
    grunt.registerTask('dev', [ // default, will run with 'grunt' only
        'less:development'
    ]);

    grunt.registerTask('default', 'dev');
};

如果您想要单独实际编译文件集（files.app、files.vendor 和files.admin），您可能需要进一步拆分任务，如下所示：

        less: {
            app: {
                options: {
                    compress: false,
                    yuicompress: true,
                    optimization: 2
                },
                files: files.app
            },
            vendor: {
                options: {
                    compress: true,
                    yuicompress: true,
                    optimization: 2
                },
                files: files.vendor
            },
            admin: {
                options: {
                    compress: true,
                    yuicompress: true,
                    optimization: 2
                },
                files: files.admin
            },
            development: {
                options: {
                    compress: false,
                    yuicompress: true,
                    optimization: 2
                },
                files: (all())
            },
            production: {
                options: {
                    compress: true,
                    yuicompress: true,
                    optimization: 2
                },
                files: (all())
            }
        },
        watch: {
            all: {
                files: ['<%= path.media %>/**/*.less'],
                tasks: ['less:development'],
                options: {
                    nospawn: true
                }
            },
            app : {
                files: ['<%= path.styles.less %>/*.less'],
                tasks: ['less:app'],
                options: {
                    nospawn: true
                }
            },
            vendor : {
                files: ['<%= path.styles.vendor %>/*.less'],
                tasks: ['less:vendor'],
                options: {
                    nospawn: true
                }
            },
            admin : {
                files: ['<%= path.styles.admin %>/*.less'],
                tasks: ['less:admin'],
                options: {
                    nospawn: true
                }
            }
        }

然后您可以运行以下任何一个：

grunt watch:app
grunt watch:vendor
grunt watch:admin

您始终可以选择直接运行任务一次：

grunt less:app
grunt less:vendor
grunt less:admin

希望这会有所帮助！请注意，我没有对此进行测试。