new-generator - new Generator class for ES2015 (ES6 Harmony) generators and iteration

This new Generator is general purpose iterable generator.

An generator is an object with a next() method that conforms to the iterable generator protocol.

The iterable generator protocol is for the next method to return the object with next value in value property in an iteration each time that is called. At the end of iteration, return the object with true in done property.

This Generator has filter, map or reduce methods like Array.

new-generator does not directly use any ES2015 (ES6 Harmony) features, but it is designed to work well with ES2015 (ES6) generators and iteration, a control flow library based on ES2015 (ES6) generators.

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Installation

$ npm install new-generator

Usage

The following example requires node v4/v5.

example using new Generator

var Generator = require('new-generator');

// new Generator with ES2015 (ES6) iteration feature (node v0.11.x)
for (var value of new Generator([11, 22, 33])
  console.log(value);
// -> 11, 22, 33

// new Generator without ES2015 (ES6) feature (node v0.8.x)
for (var gtor = new Generator([11, 22, 33]),
         n = gtor.next(); !n.done; n = gtor.next())
  console.log(n.value);
// -> 11, 22, 33

// conbination
console.log(
  new Generator(1, 20, true)                    // -> 1, 2, 3, ... 19, 20
  .filter(function (x) { return x % 2 === 0; }) // -> 2, 4, 6, ... 18, 20
  .map(function (x) { return x / 2; })          // -> 1, 2, 3, ...  9, 10
  .reduce(function (x, y) { return x + y; }));  // => 1 + 2 + ... + 10 = 55

Generator Class

new Generator(generator)

var Generator = require('new-generator');

// Number
var g1 = new Generator(3);          // -> 0, 1, 2

// String
var g2 = new Generator('abc');      // -> 'a', 'b', 'c'

// Array
var g3 = new Generator([1, 2, 3]);  // -> 1, 2, 3

// Arguments
(function() {
  var g4 = new Generator(arguments);  // -> 10, 20, 30
})(10, 20, 30);

// other Generator
var g5 = new Generator(g1);

// ES2015 (ES6) Generator
function gtorEx() {
  for (var i = 0; i < 3; ++i)
    yield i;
}
// -> 0, 1, 2
var g6 = new Generator(gtorEx);    // called with no arguments by constructor
var g7 = new Generator(gtorEx());  // normal generator

new Generator([from,] to, [step=1,] [boundary=false])

var Generator = require('new-generator');

// without boundary value (exclude last value, start from 0)
var g1 = new Generator(3);         // -> 0, 1, 2
var g2 = new Generator(0, 3);      // -> 0, 1, 2
var g3 = new Generator(0, 5, 2);   // -> 0, 2, 4
var g4 = new Generator(3, 0);      // -> 3, 2, 1
var g5 = new Generator(5, 0, -2);  // -> 5, 3, 1

// with boundary value (include last value, start from 1)
var g6 = new Generator(3, true);          // -> 1, 2, 3
var g7 = new Generator(1, 3, true);       // -> 1, 2, 3
var g8 = new Generator(1, 5, 2, true);    // -> 1, 3, 5
var g9 = new Generator(3, 1, true);       // -> 3, 2, 1
var g10 = new Generator(5, 1, -2, true);  // -> 5, 3, 1

// you can omit `new`
var g11 = Generator(3);

filter or map type of methods

Generator#filter(fn(value), this)

var Generator = require('new-generator');

console.log(new Generator(10).filter(function (x) {
  return x % 2 === 0;
}).toArray());
// -> [0, 2, 4, 6, 8]

Generator#map(fn(value), this)

var Generator = require('new-generator');

console.log(new Generator(5).map(function (x) {
  return x * 3;
}).toArray());
// -> [0, 3, 6, 9, 12]

reduce type of methods

Generator#reduce(fn(cumulative, value), initial, this)

var Generator = require('new-generator');

console.log(new Generator(10).reduce(function (x, y) {
  return x + y;
}));
// -> 55

Generator#toArray()

var Generator = require('new-generator');

console.log(new Generator(5).toArray());
// -> [0, 1, 2, 3, 4]

Generator class methods

Generator.range([from,] to, [step=1,] [boundary=false])

new Generator

Generator.count(start, [step=1])

new Generator

Generator.chain(...generators)

new Generator

etc

License

MIT

Git Repository

LightSpeedWorks/new-generator