npm-watch

2018-10-11 admin

npm-watch是什么

什么是npm-watch,run scripts from package.json when files change

npm-watch使用教程帮助文档

npm-watch

Run scripts from package.json when files change.

Synopsis

Install it:

npm install npm-watch

Add a top-level "watch" config to your package.json and a “watch” script to your "scripts":

{
  "watch": {
    "test": "{src,test}/*.js"
  },
  "scripts": {
    "test": "tape test/*.js",
    "watch": "npm-watch"
  }
}

Possibilty to watch for different tasks

  {
    "watch": 
      {
      "run_android": {
        "patterns": [
          "app"
        ],
        "extensions": "ts,html,scss",
        "quiet": false
      },
      "run_ios": {
        "patterns": [
          "app"
        ],
        "extensions": "ts,html,scss",
        "quiet": false
      }
    },
    "scripts": {
      "watch_android": "npm-watch run_android",
      "watch_ios": "npm-watch run_ios",
      "run_android": "tns run android --emulator",
      "run_ios": "tns run ios --emulator"
    }
  }

The keys of the "watch" config should match the names of your "scripts", and the values should be a glob pattern or array of glob patterns to watch.

Also it is now possible to obtain a second parameter to define the script which should be run for watching and not watch all possible scripts at once.

If you need to watch files with extensions other than those that nodemon watches by default (.js, .coffee, .litcoffee), you can set the value to an object with patterns and extensions keys. You can also add an ignore key (a list or a string) to ignore specific files. Finally, you can add a quiet flag to hide the script name in any output on stdout or stderr, or you can use the inherit flag to preserve the original’s process stdout or stderr. You can enable nodemon legacy watch and specify the restart delay in milliseconds with the corresponding flags.

The quiet flag was changed from a string to a boolean in 0.1.5. Backwards compatability will be kept for two patch versions.

Use runOnChangeOnly to set the nodemon option –on-change-only. Setting this to true tells nodemon to execute script on change only, not startup.

{
  "watch": {
    "test": {
      "patterns": ["src", "test"],
      "extensions": "js,jsx",
      "ignore": "src/vendor/external.min.js",
      "quiet": true,
      "legacyWatch": true,
      "delay": 2500,
      "runOnChangeOnly": false
    }
  },
  "scripts": {
    "test": "tape test/*.js"
  }
}

Start the watcher with npm run watch in a terminal, then edit some files:

mkdir src test
npm run watch &
cat <<EOF > test/test-sum.js
var test = require('tape')
test('sum module', function (t) {
  var sum = require('../src/sum.js')
  t.ok(sum(1, 2), 3, "Sums appear correct")
  t.end()
})
EOF

(Feel free to use the editor of your choice, cat just makes for easy demos)

You should see that your tests ran automatically, and failed because src/sum.js is missing. Let’s fix that:

cat <<EOF > src/sum.js
module.exports = function (a, b)  {
  return 1
}
EOF

Our tests will run again, and this time they almost work. Let’s fix sum.js:

cat <<EOF > src/sum.js
module.exports = function (a, b)  {
  return a + b
}
EOF

Tests run perfectly, ship it to the enterprise!

Acknowledgements

This module does very little but run nodemon for you, all credit for the reliable file watching and process restarting should go to there.

License

MIT

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