callback - Executing imported Javascript functions in order -

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i want execute 2 functions in specific have imported 2 other .js files have made. function needs complete first takes bit of time , 2nd 1 starts before first ended , need files first 1 created work. here's .js looks like:

var pdftopng = require("./pdftopng.js"); var dostufftopng = require("./dostufftopng.js");  var pdffilepath = process.argv[2];   var pngfilepath = pdftopng.convert(pdffilepath);//convert takes path                                          //and makes png , returns path                                         //to png dostufftopng.dostuff(pngfilepath); //i want "dostuff()" start after "convert()" done.

im pretty sure has callbacks, i'm javascript noob , need help. can work settimeout(), seems "duct tape fix" me. there way more elegant?

edit: wonderful people wanted , asked post this, pdftopng.js:

var spindrift= require('spindrift');//this node module var fs = require('fs');  //makes png pdf in pngfolder , returns path png exports.convert = function(path) {    var pdf = spindrift(path);    var pathtopng = path.substring(0, path.length-4); //takes off .pdf    pathtopng += "_out.png";     //this spindrift's stuff, makes png in dir pngfolder/pathtopng    pdf.pngstream(500).pipe(fs.createwritestream("pngfolder/" + pathtopng));    return "pngfolder/" + pathtopng; }

welcome async world of javascript. function callback though created synchronously executed asynchronously. have modify code dostuff executed after know sure convert function has executed. can find how can done @ why variable unaltered after modify inside of function? - asynchronous code reference


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