grunt-contrib-watch/docs/watch-options.md
XhmikosR 0c94fa2929 Update watch-options.md
Closes #451.

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2015-10-14 16:47:01 +03:00

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Settings

There are a number of options available. Please review the minimatch options here. As well as some additional options as follows:

files

Type: String|Array

This defines what file patterns this task will watch. It can be a string or an array of files and/or minimatch patterns.

tasks

Type: String|Array

This defines which tasks to run when a watched file event occurs.

options.spawn

Type: Boolean
Default: true

Whether to spawn task runs in a child process. Setting this option to false speeds up the reaction time of the watch (usually 500ms faster for most) and allows subsequent task runs to share the same context. Not spawning task runs can make the watch more prone to failing so please use as needed.

Example:

watch: {
  scripts: {
    files: ['**/*.js'],
    tasks: ['jshint'],
    options: {
      spawn: false,
    },
  },
},

For backwards compatibility the option nospawn is still available and will do the opposite of spawn.

options.interrupt

Type: Boolean
Default: false

As files are modified this watch task will spawn tasks in child processes. The default behavior will only spawn a new child process per target when the previous process has finished. Set the interrupt option to true to terminate the previous process and spawn a new one upon later changes.

Example:

watch: {
  scripts: {
    files: '**/*.js',
    tasks: ['jshint'],
    options: {
      interrupt: true,
    },
  },
},

options.debounceDelay

Type: Integer
Default: 500

How long to wait before emitting events in succession for the same filepath and status. For example if your Gruntfile.js file was changed, a changed event will only fire again after the given milliseconds.

Example:

watch: {
  scripts: {
    files: '**/*.js',
    tasks: ['jshint'],
    options: {
      debounceDelay: 250,
    },
  },
},

options.interval

Type: Integer
Default: 100

The interval is passed to fs.watchFile. Since interval is only used by fs.watchFile and this watcher also uses fs.watch; it is recommended to ignore this option. Default is 100ms.

options.event

Type: String|Array
Default: 'all'

Specify the type of watch events that triggers the specified task. This option can be one or many of: 'all', 'changed', 'added' and 'deleted'.

Example:

watch: {
  scripts: {
    files: '**/*.js',
    tasks: ['generateFileManifest'],
    options: {
      event: ['added', 'deleted'],
    },
  },
},

options.reload

Type: Boolean
Default: false

By default, if Gruntfile.js is being watched, then changes to it will trigger the watch task to restart, and reload the Gruntfile.js changes. When reload is set to true, changes to any of the watched files will trigger the watch task to restart. This is especially useful if your Gruntfile.js is dependent on other files.

watch: {
  configFiles: {
    files: [ 'Gruntfile.js', 'config/*.js' ],
    options: {
      reload: true
    }
  }
}

options.forever

Type: Boolean
Default: true

This is only a task level option and cannot be configured per target. By default the watch task will duck punch grunt.fatal and grunt.warn to try and prevent them from exiting the watch process. If you don't want grunt.fatal and grunt.warn to be overridden set the forever option to false.

options.dateFormat

Type: Function

This is only a task level option and cannot be configured per target. By default when the watch has finished running tasks it will display the message Completed in 1.301s at Thu Jul 18 2013 14:58:21 GMT-0700 (PDT) - Waiting.... You can override this message by supplying your own function:

watch: {
  options: {
    dateFormat: function(time) {
      grunt.log.writeln('The watch finished in ' + time + 'ms at' + (new Date()).toString());
      grunt.log.writeln('Waiting for more changes...');
    },
  },
  scripts: {
    files: '**/*.js',
    tasks: 'jshint',
  },
},

options.atBegin

Type: Boolean
Default: false

This option will trigger the run of each specified task at startup of the watcher.

options.livereload

Type: Boolean|Number|Object
Default: false

Set to true or set livereload: 1337 to a port number to enable live reloading. Default and recommended port is 35729.

If enabled a live reload server will be started with the watch task per target. Then after the indicated tasks have run, the live reload server will be triggered with the modified files.

See also how to enable livereload on your HTML.

Example:

watch: {
  css: {
    files: '**/*.sass',
    tasks: ['sass'],
    options: {
      livereload: true,
    },
  },
},

Passing an object to livereload allows listening on a specific port and hostname/IP or over https connections (by specifying key and cert paths).

Example:

watch: {
  css: {
    files: '**/*.sass',
    tasks: ['sass'],
    options: {
      livereload: {
        host: 'localhost',
        port: 9000,
        key: grunt.file.read('path/to/ssl.key'),
        cert: grunt.file.read('path/to/ssl.crt')
        // you can pass in any other options you'd like to the https server, as listed here: http://nodejs.org/api/tls.html#tls_tls_createserver_options_secureconnectionlistener
      }
    },
  },
},

options.cwd

Type: String|Object
Default: process.cwd()

Ability to set the current working directory. Defaults to process.cwd(). Can either be a string to set the cwd to match files and spawn tasks or an object to set each independently. Such as:

options: {
  cwd: {
    files: 'match/files/from/here',
    spawn: 'but/spawn/files/from/here'
  }
}

To strip off a path before emitting events:

options: {
  cwd: {
    files: 'a/path',
    event: 'a/path'
  }
}

This will strip off a/path before emitting events. This option is useful for specifying the base directory to use with livereload.

options.livereloadOnError

Type: Boolean
Default: true

Option to prevent the livereload if the executed tasks encountered an error. If set to false, the livereload will only be triggered if all tasks completed successfully.