node.js - How to promisify nodejs child_process exec to work with es6 -

i have phantomjs script takes url in command line args , return body html content in stdout.

when receive html content via promise call via phantomjs script call parsepage() manipulate data via cheerio , gathernext().

let cmd = '/usr/local/bin/phantomjs ' + __dirname + '/phantom.js';  let child = (command) => {     return exec(command)         .then(result => {             return result.stdout;         }); };  let parsepage = (result) => {      debug('stdout %s', result);      var $ = cheerio.load(result);      // logic - page crawl data & 've data array of objects     return resultarray };     let gathernext = (products) => {   debug('products %j', products);   allproducts = allproducts.concat(products);    if(/*not hasnextpage*/) {   return allproducts;   }   else {   return promise.resolve(cmd + ' ' + data.productlink + '&page=' + page).then(child)// this.parse({url: `&page=${page}`})       .then(parsepage)       .then(gathernext);   } };  debug('parsing page page');  return promise.resolve(cmd + ' ' + data.productlink + '&page=' + page).then(child).then(parsepage).then(gathernext); 

but not able promisify exec function? how can achieve this?

edit:

i've found lib: github.com/sindresorhus/execa resolves promise issue issue i'm getting. every next page (i.e, page - paginating 2, 3, 4, 5, etc) child func promise return old one's (first page's html content) next pages.. why happening in case? idea?

here's modified code this:

let child = (pager) => {         let command = cmdbase + pager;         console.log('command: ', command);         return execa.shell(command).then(result => {             return result.stdout;         });     }; 

or, better solution?

thanks!