io.js v3.0 is released!!!!!!!

io.js v3.0 new features.

ECMAScript 2015 - feature

current V8 version 4.4 previous V8 version 4.2

If you would like to see the changes, see the following url

https://gist.github.com/rvagg/1f115074cb3c890985bf

Computed property names

Computed property names ({['foo'+'bar']:'bam'}) are shipped. No need to specify any harmony- flag.

var i = 0;
var a = {
  ["foo" + ++i]: i,
  ["foo" + ++i]: i,
  ["foo" + ++i]: i
};

console.log(a.foo1); // 1
console.log(a.foo2); // 2
console.log(a.foo3); // 3

var param = 'size';
var config = {
  [param]: 12,
  ["mobile" + param.charAt(0).toUpperCase() + param.slice(1)]: 4
};

console.log(config);

$ iojs es6/computed_property/computedProps.js

unicode

Unicode escape sequence (\u{xxxxx}) is shipped. No need to specify --harmony option.

console.log('\u{1F363}'); // 🍣
console.log('\u{1F4A1}'); // 💡

$ iojs es6/unicode/unicode.js

Array subclass

class is already available, but previous version does not support built-in Array subclass.

note: we should put 'use strict' on top.

// strict mode needed
'use strict';
class ShuffleArray extends Array {
  shuffle() {
    var l = this.length;
    var i;
    var t;
    while (l) {
      i = Math.floor(Math.random() * l--);
      t = this[l];
      this[l] = this[i];
      this[i] = t;
    }
    return this;
  }
}

var shuffleArray = new ShuffleArray();
shuffleArray.push(1, 2, 3, 4, 5, 6);
console.log(shuffleArray.shuffle()); // shuffled [4, 6, 3, 1, 5, 2]

previous io.js is also available Array subclass. But they have an issue. v8 fixed the problem.

Spread operator

Now, we can use Spread operator (...) . But we need to specify --es_staging arguments.

The spread operator allows an expression to be expanded in places where multiple arguments (for function calls) or multiple elements (for array literals) are expected.

// Spread operator
var arr1 = [0, 1, 2];
var arr2 = [3, 4, 5];
arr1.push(...arr2); // we can use ...
console.log(arr1);

$ node --es_staging es6/spread_operator/spread.js

Rest parameters

Rest parameters (function(...args) {}) are implemented in staging behind the --es-staging flag.

// Rest parameters
function max(...args) {
  // rest parameter is not Array-like object, that is just array.
  console.log(Array.isArray(args))  // true
  console.log(args.length)          // 6

  var max = args.reduce(function(max, n) { 
    return n > max ? n : max;
  });
  return max;
}

var maxNum = max(5, 15, 10, 1, 4, 5);
console.log(maxNum); // 15

$ iojs --es_staging es6/rest_params/rest.js

REPL saves history by default

REPL gets a history file. In previous version, repl needs to specify NODE_REPL_HISTORY_FILE. But current version, repl saves history by default.

$ iojs
> var fs = require('fs');
# Ctrl-D
$ iojs
> var fs = require('fs'); # push up button

Buffer is subclass of Uint8Array

const Buffer = require('buffer').Buffer;
const ab = new ArrayBuffer(16);
var buf = new Buffer(ab); // Buffer constructor accepts ArrayBuffer.

console.log(buf instanceof Uint8Array); // true
console.log(buf instanceof Buffer); // true

buf.writeUInt32BE(0x61626364, 0);

console.log(buf.toString()); //abcd

Remove smalloc and Deprecate freelist

smalloc module is removed. freelist module is now deprecated.

Want to know more??

please check the following issue.

https://github.com/nodejs/io.js/blob/master/CHANGELOG.md#2015-08-04-version-300-rvagg https://github.com/nodejs/io.js/wiki/Breaking-Changes#300-from-2x