export default function(patterns, callback) {
    return new Promise(function(resolve, reject) {
        const chokidar = require('chokidar');

        chokidar
            .watch(patterns, { persistent: true })
            .on('change', callback)
            .on('error', reject);

        callback(patterns);
    });
}

@@ -54,28 +54,16 @@
 urn 
-new Promise(
 function
 (res
@@ -58,16 +58,22 @@
 function
+ watch
 (resolve
@@ -225,24 +225,92 @@
 hange', 
-callback
+function(file) %7B%0A                callback(file).catch(reject);%0A            %7D
 )%0A      
@@ -368,16 +368,29 @@
 rns)
+.catch(reject)
 ;%0A    %7D
-)
 ;%0A%7D%0A

refactor as Start task