Add feature --watch by including chokidar (#71)

* Add feature --watch by including chokidar

Check if the watch flag has been passed
Construct an array of expanded file paths in case it is a batched command
Load chokidar, pass input paths to its watch method
Pass minify(...) as a callback to chokidars onchange method

Author: christiankozalla

index.js

@@ -37,7 +37,8 @@ function cli(process, beforeMinifyCallback) {
     .option('--remove-inlined-files', 'Remove files inlined in <source-file ...> or via `@import` statements')
     .option('--source-map', 'Enables building input\'s source map')
     .option('--source-map-inline-sources', 'Enables inlining sources inside source maps')
-    .option('--with-rebase', 'Enable URLs rebasing');
+    .option('--with-rebase', 'Enable URLs rebasing')
+    .option('--watch', 'Runs CLI in watch mode');
 
   program.on('--help', function () {
     console.log('');
@@ -144,7 +145,15 @@ function cli(process, beforeMinifyCallback) {
 
   // ... and do the magic!
   if (program.args.length > 0) {
-    minify(process, options, configurations, expandGlobs(program.args));
+    var expandedGlobs = expandGlobs(program.args);
+    if (inputOptions.watch) {
+      var inputPaths = expandedGlobs.map(function (path) { return path.expanded; });
+      require('chokidar').watch(inputPaths).on('change', function () {
+        minify(process, options, configurations, expandedGlobs);
+      });
+    } else {
+      minify(process, options, configurations, expandedGlobs);
+    }
   } else {
     stdin = process.openStdin();
     stdin.setEncoding('utf-8');

package-lock.json

@@ -34,6 +34,7 @@
   ],
   "homepage": "https://github.com/clean-css/clean-css-cli#readme",
   "dependencies": {
+    "chokidar": "^3.5.2",
     "clean-css": "^5.2.2",
     "commander": "7.x",
     "glob": "^7.1.6"