Run arbitrary commands when files are changed while running serverless-offline

npm install --save-dev serverless-offline-watcher

Add it to your list of plugins, and custom config for what you want to do on files being changed.

The path property may be a string, or array of strings. They be file paths, directory paths or glob patterns. Under the hood this library uses chokidar for file watching and picomatch for glob patterns, so you can see there documentation for more details about supported patterns.

The event type and the changed file path are available in environment variables WATCHER_EVENT_TYPE and WATCHER_EVENT_PATH respectively. The event type comes from chokidar and is one of "add" | "addDir" | "change" | "unlink" | "unlinkDir".

serverless.yaml:

plugins:
  - serverless-offline
  - serverless-offline-watcher
custom:
  serverless-offline-watcher:
    - path: src/index.ts
      command: echo "index.ts was modified!"
    - path:
        - src/api
        - src/cow/*.js
      command:
        - echo "api folder or js file in cow folder was modified!"
        - echo "the command-option can also be an array of commands"
    - path:
        - src/**/**
      # this prints for example "received change event for src/path/to/file.ts"
      command: "echo received $WATCHER_EVENT_TYPE event for $WATCHER_EVENT_PATH"

serverless.js / serverless.ts:

export default {
  plugins: [
    "serverless-offline",
    "serverless-offline-watcher",
  ],
  custom: {
    'serverless-offline-watcher': [
      {
        path: "src/index.ts",
        command: `echo "index.ts was modified!"`,
      },
      {
        path: ["src/api", "src/cow/*.js"],
        command: `echo "api folder or js file in cow folder was modified!"`,
      },
    ],
  },
}

In addition to running arbitrary shell commands, the plugin can also invoke a hook in some other serverless plugin, with the hook option. The following will ask serverless-offline to clear its Worker cache when a file in the src directory is changed:

    - path:
        - src/**/*
      hook:
        - offline:functionsUpdated

Use serverless offline start instead of serverless offline, if you aren't already. This is necessary for serverless-offline to fire off init and end lifecycle hooks so that we can start and stop the watch server correctly.