watch-trigger

watch-trigger

A simple utility script that associates file pattern lists with commands to run when a change in one of those files is detected. Uses simple file polling to maximize consistently across platforms (at the expense of some performance).

Usage

Create configuration file in your project. It describes the files to include in the watch set and the command to run when any of those files change:

{
    "include" : "src/**/*",
    "command" : "make build --no-print-directory"
}

Then run watch-trigger with that configuration file:

node node_modules/watch-trigger/index.js my-config.json

Configuration

The configuration file can be written as either JSON or JavaScript. If it is written in JavaScript, the module.exports should be a JSON object.

Single file set configuration

{
  "include" : <glob pattern> OR [ <array of glob patterns> ],
  "exclude" : <glob pattern> OR [ <array of glob patterns> ],

  "command" : <command string>,
  **OR**
  "commands": [ <array of sequential command strings> ],
}

Multiple file set configuration

If multiple sets of glob patterns and commands are required, an array of sets can be used:

{
  "sets" : [
    {
  		"include" : ...,
  		"exclude" : ...,
  		"command" : ...,
    },
    {
  		"include" : ...,
  		"commands" : [ ... ],
    },
    ...
  ]
}

Command string

The command string is passed directly to the shell for execution (using child_process.execSync), with one exception:

• The literal$1 will be replaced with the filename of the file whose modification triggered the command

before option

The before configuration option can be used to describe command(s) that are run exactly once before the watch starts. watch-tigger does not wait for these commands to finish before starting the watch.

For example, this would start the dev-server (and presumably leave it running) and re-run the build-assets target whenever an asset file changed without restarting the dev-server.

{
    "before" : "make dev-server --no-print-directory",
    "include" : "src/assets/**/*",
    "command" : "make build-assets --no-print-directory"
}