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https://github.com/swannodette/mori

ClojureScript's persistent data structures and supporting API from the comfort of vanilla JavaScript
https://github.com/swannodette/mori

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ClojureScript's persistent data structures and supporting API from the comfort of vanilla JavaScript

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README 

        
# mori



Mori



A simple bridge to ClojureScript's persistent data structures and

[supporting APIs](http://swannodette.github.io/mori/) for vanilla

JavaScript. Pull requests welcome.



## Breaking changes in 0.3.0 



The API now uses idiomatic JavaScript naming conventions.



## Improvements to 0.3.0



### Faster



Mori is considerably faster across the board thanks to recent

enhancements to the ClojureScript compiler. For users who would like

to benchmark their immutable data structure implementations against

Mori, Mori now exposes direct arity invokes which eliminates previous

calling overheads from arity dispatching. See

[Benchmarking](https://github.com/swannodette/mori/wiki/Benchmarking)

for more information.



Mori hash maps now default to ClojureScript `ArrayMap`s that are

automatically promoted to `PersistentHashMap`s as needed. `ArrayMap`s

deliver considerably better performance at small sizes and when simple

keys are at play. For example a Mori hash map with less than or equal

to eight keys can now be built nearly an order of magnitude faster than

Immutable.js 3.6.2 `Map`s.



### More ES6



All Mori collections support ES6 iteration via `foo[Symbol.iterator]`

or `foo["@@iterator"]`.



## Differences from Immutable.js



* A functional API, data structures do not have public methods

* Faster, ClojureScript data structures have been subjected to more

  real world usage and continuous benchmarking for nearly 4 years

* Larger, gzipped the base Mori module is about 6K larger than Immutable.js



## Getting it



You can install the latest release via npm:



```shell

npm install mori

```



The installed package contains a single optimized JavaScript file `mori.js`.



Load `mori` in your Node.js programs as you would any other module:



```javascript

var mori = require("mori");

```



In a browser, you can load mori with a script tag, as you would any other JavaScript library:



```html



```



You can also load it as an AMD module, e.g. with [RequireJS](http://requirejs.org/).



## Usage



You can use it from your projects like so:



```javascript

var inc = function(n) {

  return n+1;

};



mori.intoArray(mori.map(inc, mori.vector(1,2,3,4,5)));

// => [2,3,4,5,6]

```



Efficient non-destructive updates!



```javascript

var v1 = mori.vector(1,2,3);

var v2 = mori.conj(v1, 4);

v1.toString(); // => '[1 2 3]'

v2.toString(); // => '[1 2 3 4]'

```



```javascript

var sum = function(a, b) {

  return a + b;

};

mori.reduce(sum, mori.vector(1, 2, 3, 4)); // => 10

```



Lazy sequences!



```javascript

var _ = mori;

_.intoArray(_.interpose("foo", _.vector(1, 2, 3, 4)));

// => [1, "foo", 2, "foo", 3, "foo", 4]

```



Or if it's more your speed, use it from CoffeeScript!



```coffeescript

inc = (x) -> x+1  

r = mori.map inc, mori.vector(1,2,3,4,5)

mori.intoArray r

```



### Documentation



You can find extensive [documentation and examples](http://swannodette.github.io/mori/) here.



## More Examples



### Efficient Freeze/Thaw



For vectors and maps we provide an efficient thaw and freeze

operations:



```javascript

var m = mori;



// ~220ms with V8 version 3.29.80 MBP 2.26ghz

for(var j = 0; j < 10; j++) {

  var s = new Date();

  var arr = [];

  for(var i = 0; i < 10000000; i++) {

    arr.push(i);

  }

  print("Array push " + arr.length + " items " + ((new Date())-s));

  gc();

}



// ~70ms

for(var j = 0; j < 10; j++) {

  s = new Date();

  var mv = m._thaw(m.vector());

  for(var i = 0; i < 10000000; i++) {

    mv = m._conj.f2(mv, i);

  }

  var v = m._freeze(mv);

  print("Mutable vector conj " + m.count(v) + " items " + ((new Date())-s));

  gc();

}

```



### ES6 Map/Set inspired interfaces



All Mori maps and sets support all the non-mutating methods of the

proposed ES6

[Map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map)

and

[Set](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set)

interfaces. The main difference with the spec is that key lookup is

based on value not reference. `keys`, `values`, and `entries` methods

return the proposed mutable iterators:



```javascript

var m = mori;

var h = m.hashMap("foo", 1, "bar", 2);



h.has("foo"); // => true

h.get("foo"); // => 1



var iter = h.keys();

iter.next(); // => {done: false, value: "foo"}

```



This feature is subject to changes in the ES6 proposal.



### Transducers



Mori includes Transducers. Zero allocation collection operations FTW:



```javascript

var m = mori;

var a = [];



for(var i = 0; i < 1000000; i++) {

  a.push(i);

}



// make it immutable

var v = m.into(m.vector(), a);



function time(f) {

  var s = new Date();

  f();

  console.log(((new Date())-s)+"ms");

}



// ~190ms V8 version 3.29.80 MBP 2.26ghz

time(function() {

  var xf = m.comp(m.map(m.inc), m.map(m.inc), m.map(m.inc));

  return m.transduce(xf, m.completing(m.sum), 0, v);

}, 10);



// ~440ms

time(function() {

  return a.map(m.inc).map(m.inc).map(m.inc).reduce(function(a,b){return a+b;}, 0);

}, 10);

```



## Build



### Prerequisites



You will first need to install the

[Java](http://www.oracle.com/technetwork/java/javase/downloads/index.html)

SDK, if it's not already installed on your system.



On Windows, you will need to manually install

[Leiningen](http://github.com/technomancy/leiningen). On UNIX-like

systems, Leiningen will be installed within the project automatically

if the `lein` executable is not found on your path or if your `lein`

version predates `2.0.0`.



### Clone the repo



```shell

git clone https://github.com/swannodette/mori.git

cd mori

```



### On a UNIX-like system build with



```shell

./scripts/build.sh

```



### Alternatively using npm



```shell

npm run-script build

```



### On Windows



```shell

./scripts/build.ps1

```



The build process will generate an optimized JavaScript file

`mori.js`, which is suitable for use with Node.js, or in a Web browser

or other JavaScript environments. You can also load it as an AMD

module.



Copyright (C) 2012-2015 David Nolen and contributors



Distributed under the

[Eclipse Public License](https://raw.github.com/swannodette/mori/master/epl-v10.html),

the same as Clojure.