npm run-scripts boilerplate

package.json

{
    "name": "my-app",
    "version": "1.0.0",
    "description": "My test app",
    "main": "src/js/index.js",
    "scripts": {
        "jshint:dist": "jshint src/js/*.js",
        "jshint": "npm run jshint:dist",
        "jscs": "jscs src/*.js",
        "browserify": "browserify -s Validating -o ./dist/js/build.js ./lib/index.js",
        "browsersync": "browser-sync start --server --files 'src/*'",
        "uglify:dist": "uglify src/js/**/*.js > dist/js/script.min.js",
        "uglify": "npm run uglify:dist",
        "test": "mocha",
        "clean:dist": "rm -rf dist",
        "clean:tmp": "rm -rf tmp",
        "clean": "npm run clean:dist && npm run clean:tmp",
        "copy:dist": "cp src/*.{js,css,html} dist/",
        "copy": "npm run copy:dist",
        "sass:dist": "sass src/css/style.scss > dist/css/style.min.css",
        "sass": "npm run sass:dist",
        "htmlmin:dist": "htmlmin -cs dist/index.html tmp/index.html",
        "imagemin": "imagemin src/images/* dist/images/* -p",
        "build:html": "npm run htmlmin",
        "build:js": "npm run jshint && npm run uglify",
        "build:css": "npm run sass",
        "build:images": "npm run imagemin",
        "build": "npm run clean && npm run build:html && npm run build:js && npm run build:css && npm run build:imagemin",
        "watch": "watch 'npm run build' ."
    },
    "dependencies": {
        "jshint": "latest",
        "imagemin": "latest",
        "browser-sync": "latest",
        "uglifyjs": "latest",
        "watch": "latest",
        "cssmin": "latest",
        "jscs": "latest",
        "uglify-js": "latest",
        "browserify": "latest",
        "expect.js": "latest",
        "should": "latest",
        "mocha": "latest",
        "istanbul": "latest"
    }
}

This is nothing new or ground-breaking but worth pointing out here for others that find this.

Instead of running the entire build when a change occurs on any file, prefer to run only the script/task related to the changed file. Personally, I like chokidar-cli for this purpose.

In the command that you want chokidar to run on file change (passed via the -c argument) you can use grep to check for a pattern in the changed file path and respond accordingly.

...
"watch": "chokidar './src/**/*' -c 'if grep -q \".scss\" \"{path}\"; then npm run sass; elif grep -q \".html\" \"{path}\"; then npm run html; fi;'",
"sass": "node-sass ./src/scss/main.scss -o ./dist/css/",
"html": "cpx './src/**/*.html' ./dist"
...

In the above example, if the file path contains .scss the sass script runs. If the path contains .html the html script runs.

Furthermore, you can combine this with npm script arguments to pass the file path along to the given script. For example...

...
"watch": "chokidar './src/**/*' -c 'if grep -q \".scss\" \"{path}\"; then npm run sass; elif grep -q \".html\" \"{path}\"; then npm run html -- \"{path}\" ./dist; fi;'",
"sass": "node-sass ./src/scss/main.scss -o ./dist/css/",
"html": "cpx"
...

So, in this example we're passing the {path} variable provided by chokidar to the html script so only the single, changed file is processed. Benefits are speed and fewer browser reloads when using lite-server or browser-sync. And it's freakin' sweet.