Stream.js

An simple lazy evaluated stream API in Javascript inspired by Java 8 stream

Installation

npm install lazy-streamjs

API

$3

You can use the global object stream to create your stream:
##### stream.range(from, to)
Get a new stream of numbers in the range [from, to[

##### stream.function(generatorFunction)
Get a new stream from a function generatorFunction called everytime a new element is needed

##### stream(data);
Get a Stream from your collection (Array, Object or String) passing it to stream function:

$3

Apply intermediate operations to the stream by just concatenating them:

##### .map(mapFunction)
Map all elements using mapFunction

##### .filter(filterFunction)
Take only elements that satisfy the predicate filterFunction

##### .take(n)
Take first n elements of the stream

##### .foldl(foldlFunction, base)
Apply foldl using foldlFunction and base as base case

##### .foldr(foldrFunction, base)
Apply foldr using foldrFunction and base as base case

$3

You can get the result using:

##### .getNext()
Will get back the next element of the stream or null at the end

##### .getAll()
Will get back all the elements of the stream

$3

``javascript
var stream = require('lazy-streamjs');

var data = [-2, -100, 2, 1, 2, 3, 4];
var result = stream(data)
.map(function(x) { return x + 1; })
.filter(function(x) { return x > 0; })
.getAll();

console.log(result);
`
Will print

3
2
3
4
5

`javascript
var stream = require('lazy-streamjs');

var fibGenerator = (function() {
var e1 = 0,
e2 = 1;

return function() {
var next = e1 + e2;
e1 = e2;
e2 = next;

return next;
}

})();

res = Stream.function(fibGenerator)
.take(10)
.getAll();
``
Will print the first 10 elements of the Fibonacci Series (will not cause an infinite loop because of it's lazy evaluated)