Copy & paste

I sometime just need to test something quickly. And so I copy & paste an example from internet.

This is usually doesn't work out of the box... But I have some tips and tricks to get this working.

debuggin aka console.log

In Haxe you usually use the Haxe specific way of logging: trace()

But you can always use the platform specific way. In the case of JavaScript:


A handy shortcut for console.log is in package js.Browser

So you could rewrite everything to that:

// console.log('foo');

But it's MUCH easier to add it to you imports

import js.Browser.console;     // if you only want to use console.log
import js.Browser.*;         // if you also want to use window, document, alert, etc

and then your console.log will just work without any changes to the copied code

document, window, console, location

Pretty much the same as previous example. This is easily fixed with the correct import:

import js.Browser.*;

And then a simple VanillaJS example works out of the box.

document.addEventListener("DOMContentLoaded", function(event) {
    console.log("VanillaJs DOM ready");
    trace('host: ',;


Haxe has jQuery externs embedded in the compiler, but there are some differences using it.

For a typical JS starting point with jQuery, you write:

    //do your magic

You probably don't realise it but it's a short-hand that bind your magic codes to the document ready event, same as if you write:

    //do your magic

Both will result in Unknown identifier : $

So both code-examples won't work in Haxe, because Haxe does not allow using $ as a class name or a function name. But $ is just a short-hand to jQuery so we should be able to fix that.... except... Haxe requires all class names start with capital letter, so it is JQuery in Haxe and not jQuery.

You start your Haxe/JS codes using the jQuery extern as following:

import js.jquery.JQuery;

class Main {
    static public function main():Void {
        new JQuery(function():Void { //when document is ready
            //your magic

So in short: you replace $( ... ) with new JQuery( ... ), import js.jquery.JQuery; and it will work.

For more examples check the chapter jQuery.

for loop

Okay this thing will not work!

JavaScript uses a classic C-style for-loop

for (i = 0; i < 100; i++) {

Haxe uses a iterator based for-loop You will have to change that to:

for (i in 0...100) {

For more examples check cheatsheet.html#loops.


Mostly its just search where the packages are located Its to difficult to get you out off all your copy pasting, but for example:

var req = new XMLHttpRequest();

works with the correct import

import js.html.XMLHttpRequest;

Sometimes you just need to add new:


doesn't work, even if you have imported the correct package

import js.Error;

just call the constructor:

reject(new Error(req.statusText));


Most copy paste stuff is easy fixed, so is this one. But the solution has something to do with a different language decision.

In Haxe you will create a date with new Date(year, month, day, hour, min, sec) In JS it will return the current date

new Date ()

So use this in Haxe, this will return the current date.;


Repeating calls are create with setInterval in JS.

var timer = setInterval(function () {
  // do something
}, 1000);

// clearInterval(timer); // stop interval

But with this code the compiler will complain: Unknown identifier : setInterval

You can replace this with the default Haxe Timer methode.

var timer = new haxe.Timer(1000); // 1000ms delay = function() {
  // do something

// timer.stop(); // stop interval

For some reason I usually use the "dirty" solution: use untyped

var timer = untyped setInterval(function () {
  // do something
}, 1000);

// untyped clearInterval(timer); // stop interval

But I shouldn't learn bad stuff, so this is the official Haxe solution:

var timer = js.Browser.window.setInterval(function () {
  // do something
}, 1000);

// js.Browser.window.clearInterval(timer); // stop interval


Delayed calls are create with setTimeout in JS.

setTimeout(function () {
  // do something
}, 5000);

But with this code the compiler will complain: Unknown identifier : setTimeout

You can replace this with the default Haxe Timer.delay methode.

haxe.Timer.delay(function() {
  // do something
}, 5000);

For some reason I usually use the "dirty" solution: use untyped

untyped setTimeout(function () {
  // do something
}, 5000);

But I shouldn't learn bad stuff, so this is the official Haxe solution:

js.Browser.window.setTimeout(function () {
  // do something
}, 5000);


Okay .... Stupid but JavaScript is more flexible with this. Just follow the instructions from the Haxe compiler.

Start document

Okay maybe a little much but I use this example / test document a lot... Perhaps someone has some use for it.


package ;

import js.Browser.*;

class Main
    function new() {

    static public function main(){
        var main = new Main();


-cp src
-main Main
-js bin/example.js
-D source-map-content
-dce full

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