setTimeout polyfill for Nashorn

setTimeout-nashorn.js

// https://gist.github.com/josmardias/20493bd205e24e31c0a406472330515a
// at least one timeout needs to be set, larger then your code bootstrap
//  or Nashorn will run forever
// preferably, put a timeout 0 after your code bootstrap

(function(context) {
  'use strict';

  var Timer = Java.type('java.util.Timer');
  var Phaser = Java.type('java.util.concurrent.Phaser');

  var timer = new Timer('jsEventLoop', false);
  var phaser = new Phaser();

  var timeoutStack = 0;
  function pushTimeout() {
    timeoutStack++;
  }
  function popTimeout() {
    timeoutStack--;
    if (timeoutStack > 0) {
      return;
    }
    timer.cancel();
    phaser.forceTermination();
  }

  var onTaskFinished = function() {
    phaser.arriveAndDeregister();
  };

  context.setTimeout = function(fn, millis /* [, args...] */) {
    var args = [].slice.call(arguments, 2, arguments.length);

    var phase = phaser.register();
    var canceled = false;
    timer.schedule(function() {
      if (canceled) {
        return;
      }

      try {
        fn.apply(context, args);
      } catch (e) {
        print(e);
      } finally {
        onTaskFinished();
        popTimeout();
      }
    }, millis);

    pushTimeout();

    return function() {
      onTaskFinished();
      canceled = true;
      popTimeout();
    };
  };

  context.clearTimeout = function(cancel) {
    cancel();
  };

  context.setInterval = function(fn, delay /* [, args...] */) {
    var args = [].slice.call(arguments, 2, arguments.length);

    var cancel = null;

    var loop = function() {
      cancel = context.setTimeout(loop, delay);
      fn.apply(context, args);
    };

    cancel = context.setTimeout(loop, delay);
    return function() {
      cancel();
    };
  };

  context.clearInterval = function(cancel) {
    cancel();
  };

})(this);

test.js

// (TEST) /usr/java/default/bin/jjs setTimeout-nashorn.js test.js

console.log(1)

t1 = setTimeout(function () {
  console.log(4);
}, 300)

console.log(2)

t2 = setTimeout(function () {
  console.log(3);
}, 200)

clearTimeout(t1)

// OUTPUT: 
// 1
// 2
// 3

test2.js

// (TEST) /usr/java/default/bin/jjs setTimeout-nashorn.js test2.js

console.log('start')

var i = 0;
t1 = setInterval(function () {
  console.log('i-' + ++i);
}, 10)

t2 = setTimeout(function () {
  clearInterval(t1)
  console.log('end')
}, 100)


// OUTPUT:
// start
// i-1
// i-2
// i-3
// i-4
// i-5
// i-6
// i-7
// i-8
// end

Hi! Just wanted to let you know, I'm thinking of using this nice code in my own NPM package (as one of several side dependencies for rendering react from nashorn). I credited you early in the readme. Work in progress: https://www.npmjs.com/package/react4xp-runtime-nashornpolyfills

I'm still a bit new to the ancient ways of open-sourcing, so I hope this sounds okay and everything about the usage looks fine - please let me know if not.

Thanks! :)

• Espen,
  espen42@gmail.com