phpjs/_octopress/source/functions/round/index.markdown

php.js offers community built php functions in javascript

---
layout: page
title: "JavaScript round function"
comments: true
sharing: true
footer: true
alias:
- /functions/view/round:505
- /functions/view/round
- /functions/view/505
- /functions/round:505
- /functions/505
---
<!-- Generated by Rakefile:build -->
A JavaScript equivalent of PHP's round

{% codeblock math/round.js lang:js https://raw.github.com/kvz/phpjs/master/functions/math/round.js raw on github %}
function round (value, precision, mode) {
  // From: http://phpjs.org/functions
  // +   original by: Philip Peterson
  // +    revised by: Onno Marsman
  // +      input by: Greenseed
  // +    revised by: T.Wild
  // +      input by: meo
  // +      input by: William
  // +   bugfixed by: Brett Zamir (http://brett-zamir.me)
  // +      input by: Josep Sanz (http://www.ws3.es/)
  // +    revised by: Rafał Kukawski (http://blog.kukawski.pl/)
  // %        note 1: Great work. Ideas for improvement:
  // %        note 1:  - code more compliant with developer guidelines
  // %        note 1:  - for implementing PHP constant arguments look at
  // %        note 1:  the pathinfo() function, it offers the greatest
  // %        note 1:  flexibility & compatibility possible
  // *     example 1: round(1241757, -3);
  // *     returns 1: 1242000
  // *     example 2: round(3.6);
  // *     returns 2: 4
  // *     example 3: round(2.835, 2);
  // *     returns 3: 2.84
  // *     example 4: round(1.1749999999999, 2);
  // *     returns 4: 1.17
  // *     example 5: round(58551.799999999996, 2);
  // *     returns 5: 58551.8
  var m, f, isHalf, sgn; // helper variables
  precision |= 0; // making sure precision is integer
  m = Math.pow(10, precision);
  value *= m;
  sgn = (value > 0) | -(value < 0); // sign of the number
  isHalf = value % 1 === 0.5 * sgn;
  f = Math.floor(value);

  if (isHalf) {
    switch (mode) {
    case 'PHP_ROUND_HALF_DOWN':
      value = f + (sgn < 0); // rounds .5 toward zero
      break;
    case 'PHP_ROUND_HALF_EVEN':
      value = f + (f % 2 * sgn); // rouds .5 towards the next even integer
      break;
    case 'PHP_ROUND_HALF_ODD':
      value = f + !(f % 2); // rounds .5 towards the next odd integer
      break;
    default:
      value = f + (sgn > 0); // rounds .5 away from zero
    }
  }

  return (isHalf ? value : Math.round(value)) / m;
}
{% endcodeblock %}

 - [Raw function on GitHub](https://github.com/kvz/phpjs/blob/master/functions/math/round.js)

Please note that php.js uses JavaScript objects as substitutes for PHP arrays, they are 
the closest match to this hashtable-like data structure. 

Please also note that php.js offers community built functions and goes by the 
[McDonald's Theory](https://medium.com/what-i-learned-building/9216e1c9da7d). We'll put online 
functions that are far from perfect, in the hopes to spark better contributions. 
Do you have one? Then please just: 

 - [Edit on GitHub](https://github.com/kvz/phpjs/edit/master/functions/math/round.js)

### Example 1
This code
{% codeblock lang:js example %}
round(1241757, -3);
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
1242000
{% endcodeblock %}

### Example 2
This code
{% codeblock lang:js example %}
round(3.6);
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
4
{% endcodeblock %}

### Example 3
This code
{% codeblock lang:js example %}
round(2.835, 2);
{% endcodeblock %}

Should return
{% codeblock lang:js returns %}
2.84
{% endcodeblock %}


### Other PHP functions in the math extension
{% render_partial _includes/custom/math.html %}