tree-kit

What is tree-kit?

The tree-kit npm package provides utilities for manipulating and traversing tree-like structures in JavaScript. It offers a variety of functions to work with nested objects and arrays, making it easier to manage hierarchical data.

What are tree-kit's main functionalities?

Deep cloning

This feature allows you to create a deep clone of an object, ensuring that nested objects are also cloned rather than referenced.

const tree = require('tree-kit');
const original = { a: 1, b: { c: 2 } };
const clone = tree.clone(original);
console.log(clone); // { a: 1, b: { c: 2 } }

Deep merging

This feature allows you to merge multiple objects deeply, combining their properties and nested structures.

const tree = require('tree-kit');
const obj1 = { a: 1, b: { c: 2 } };
const obj2 = { b: { d: 3 }, e: 4 };
const merged = tree.extend(null, obj1, obj2);
console.log(merged); // { a: 1, b: { c: 2, d: 3 }, e: 4 }

Path-based access

This feature allows you to access nested properties using a dot-separated path string, making it easier to retrieve deeply nested values.

const tree = require('tree-kit');
const obj = { a: { b: { c: 42 } } };
const value = tree.get(obj, 'a.b.c');
console.log(value); // 42

Path-based setting

This feature allows you to set nested properties using a dot-separated path string, making it easier to update deeply nested values.

const tree = require('tree-kit');
const obj = { a: { b: { c: 42 } } };
tree.set(obj, 'a.b.d', 100);
console.log(obj); // { a: { b: { c: 42, d: 100 } } }

Other packages similar to tree-kit

lodash

Lodash is a popular utility library that provides a wide range of functions for manipulating arrays, objects, and other data structures. It includes deep cloning and merging functionalities similar to tree-kit, but also offers a broader set of utilities for general-purpose programming.

deepmerge

Deepmerge is a specialized library for deep merging of JavaScript objects. It focuses specifically on merging nested structures, similar to the deep merging feature of tree-kit, but does not offer the broader range of tree manipulation utilities.

dot-prop

Dot-prop is a utility for accessing and manipulating object properties using dot-separated path strings. It provides similar path-based access and setting functionalities as tree-kit, but is more focused on these specific operations.

README

Tree Kit

This lib is a toolbox that provide functions to operate with nested Object structure. It features the classic .extend() method, but provide a whole bunch of options that the others library lack.

• License: MIT
• Current status: beta
• Platform: Node.js only (browser support is planned)

Install

Use Node Package Manager:

npm install tree-kit

Library references

In all examples below, it is assumed that you have required the lib into the tree variable:

var tree = require( 'tree-kit' ) ;

.extend( options , target , source1 , [source2] , [...] )

• options Object extend options, it supports the properties:
  • own boolean only copy owned properties from the sources
  • deep boolean perform a deep (recursive) extend
  • move boolean move properties from the sources object to the target object (delete properties from the sources object)
  • preserve boolean existing properties in the target object will not be overwritten
  • nofunc boolean skip properties that are functions
  • proto boolean alter the target's prototype so that it matches the source's prototype. It forces option 'own'. Specifying multiple sources does not make sens here.
  • inherit boolean make the target inherit from the source (the target's prototype will be the source itself, not its prototype). It forces option 'own' and disable 'proto'. Specifying multiple sources does not make sens here.
  • skipRoot boolean prevent the prototype of the target root object from mutation. Only nested objects' prototype will be mutated.
  • flat boolean|string sources properties are copied in a way to produce a flat target, the target's key is the full path (separated by '.') of the source's key, also if a string is provided it will be used as the path separator
  • unflat boolean|string it is the opposite of 'flat': assuming that the sources are in the flat format, it expands all flat properties -- whose name are path with '.' as the separator -- deeply into the target, also if a string is provided it will be used as the path separator
  • deepFilter Object filter the recursiveness of the 'deep' option, filtered objects will be referenced just the way it would be if the 'deep' option was turned off, objects are filtered based upon their prototypes (only direct prototype match, for performance purpose the rest of the prototype chain will not be checked)
    • blacklist Array list of black-listed prototype
    • whitelist Array list of white-listed prototype
• target Object the target of the extend, properties will be copied to this object
• source Object the source of the extend, properties will be copied from this object

This is a full-featured extend of an object with one or more source object.

It is easily translated from jQuery-like extend():

• extend( target , source ) translate into tree.extend( null , target , source )
• extend( true , target , source ) translate into tree.extend( { deep: true } , target , source )

However, here we have full control over what will be extended and how.

By default, tree.extend() will copy all enumerable properties, and perform a shallow copy (a nested object is not cloned, it remains a reference of the original one).

With the deep option, a deep copy is performed, so nested object are cloned too.

The own option clone only owned properties from the sources, properties that are part of the source's prototype would not be copied/cloned.

You can also clone an object as close as it is possible to do in javascript by doing this:

var clone = tree.extend( { deep: true, proto: true } , null , original ) ;

Also please note that:

• properties that are not enumerable will never be cloned: javascript does not provide a way to search for them
• design pattern using private members cannot be truly cloned since those private members are hidden in an inaccessible closure's scope

Mixing inherit and deep provides a nice multi-level inheritance.

With the flat option example:

var o = {
	one: 1,
	sub: {
		two: 2,
		three: 3
	}
} ;

var flatCopy = tree.extend( { flat: true } , {} , o ) ;

... it will produce:

{
	one: 1,
	"sub.two": 2,
	"sub.three": 3
}

By the way, the unflat option does the opposite, and thus can reverse this back to the original form.

The deepFilter option is used when you do not want to clone some type of object. Let's say you want a deep copy except for Buffer objects, you simply want them to share the same reference:

var o = {
	one: '1' ,
	buf: new Buffer( "My buffer" ) ,
	subtree: {
		two: 2 ,
		three: 'THREE'
	}
} ;

// either
var extended1 = tree.extend( { deep: true, deepFilter: { whitelist: [ Object.prototype ] } } , {} , o ) ;
// or
var extended2 = tree.extend( { deep: true, deepFilter: { blacklist: [ Buffer.prototype ] } } , {} , o ) ;

Doing this, we have o.buf === extended1.buf === extended2.buf, and o.subtree !== extended1.subtree !== extended2.subtree.

.diff( left , right , [options] )

• left Object the left-hand side object structure
• right Object the right-hand side object structure
• options Object containing options, it supports:
  • path string the initial path, default: empty string
  • pathSeparator string the path separator, default: '.'

This tool reports diff between a left-hand side and right-hand side object structure. It returns an object, each key is a path where a difference is reported, the value being an object containing (again) the path and a human-readable message.

See this example:

var left = {
	a: 'a',
	b: 2,
	c: 'three',
	sub: {
		e: 5,
		f: 'six',
	}
} ;

var right = {
	b: 2,
	c: 3,
	d: 'dee',
	sub: {
		e: 5,
		f: 6,
	}
} ;

console.log( tree.diff( a , b ) ) ;

It will output:

{ '.a': { path: '.a', message: 'does not exist in right-hand side' },
  '.c': { path: '.c', message: 'different typeof: string - number' },
  '.sub.f': { path: '.sub.f', message: 'different typeof: string - number' },
  '.d': { path: '.d', message: 'does not exist in left-hand side' } }

Full BDD spec generated by Mocha:

TOC

• extend()
• Diff
• Masks
• Inverse masks

extend()

should extend correctly an empty Object with a flat Object without depth (with or without the 'deep' option).

var copy ;

var expected = {
	d : 4 ,
	e : undefined ,
	f : 3.14 ,
	g : 6 ,
	h : [] ,
	i : 'iii'
} ;

copy = tree.extend( { deep: true } , {} , input.subtree.subtree ) ;
expect( tree.extend( null , copy , input.subtree.subtree2 ) ).to.eql( expected ) ;

copy = tree.extend( { deep: true } , {} , input.subtree.subtree ) ;
expect( tree.extend( { deep: true } , copy , input.subtree.subtree2 ) ).to.eql( expected ) ;

should extend an empty Object with a deep Object performing a SHALLOW copy, the result should be equal to the deep Object, nested object MUST be equal AND identical.

var copy = tree.extend( null , {} , input.subtree ) ;
expect( copy ).to.eql( input.subtree ) ;
expect( copy ).not.to.equal( input.subtree ) ;
expect( copy.subtree2 ).to.equal( input.subtree.subtree2 ) ;

with the 'deep' option should extend an empty Object with a deep Object performing a DEEP copy, the result should be equal to the deep Object, nested object MUST be equal BUT NOT identical.

var copy = tree.extend( { deep: true } , {} , input.subtree ) ;
expect( copy ).to.eql( input.subtree ) ;
expect( copy ).not.to.equal( input.subtree ) ;
expect( copy.subtree2 ).not.to.equal( input.subtree.subtree2 ) ;

should extend (by default) properties of the prototype chain.

var proto = {
	proto1: 'proto1' ,
	proto2: 'proto2' ,
} ;

var o = Object.create( proto ) ;

o.own1 = 'own1' ;
o.own2 = 'own2' ;

expect( tree.extend( null , {} , o ) ).to.eql( {
	proto1: 'proto1' ,
	proto2: 'proto2' ,
	own1: 'own1' ,
	own2: 'own2'
} ) ;

expect( tree.extend( { deep: true } , {} , o ) ).to.eql( {
	proto1: 'proto1' ,
	proto2: 'proto2' ,
	own1: 'own1' ,
	own2: 'own2'
} ) ;

with the 'own' option should ONLY extend OWNED properties, properties of the prototype chain are SKIPPED.

var proto = {
	proto1: 'proto1' ,
	proto2: 'proto2' ,
} ;

var o = Object.create( proto ) ;

o.own1 = 'own1' ;
o.own2 = 'own2' ;

expect( tree.extend( { own: true } , {} , o ) ).to.eql( {
	own1: 'own1' ,
	own2: 'own2'
} ) ;

expect( tree.extend( { deep: true, own: true } , {} , o ) ).to.eql( {
	own1: 'own1' ,
	own2: 'own2'
} ) ;

with the 'deep' option should extend a deep Object into another deep Object correctly.

var copy ;

copy = tree.extend( { deep: true } , {} , input.subtree ) ;
expect( tree.extend( null , copy , input.anotherSubtree ) ).to.eql( {
	a : 'A' ,
	b : 2 ,
	subtree: {
		l : '1one' ,
		m : false ,
		n : 'nay'
	} ,
	c : 'plusplus' ,
	subtree2: {
		p : true ,
		q : [4,5,6] ,
		r : '2'
	} ,
	j : 'Djay' ,
	k : 'ok' ,
	o : 'mg'
} ) ;

copy = tree.extend( { deep: true } , {} , input.subtree ) ;
expect( tree.extend( { deep: true } , copy , input.anotherSubtree ) ).to.eql( {
	a : 'A' ,
	b : 2 ,
	subtree: {
		d : 4 ,
		e : undefined ,
		f : 3.14 ,
		l : '1one' ,
		m : false ,
		n : 'nay'
	} ,
	c : 'plusplus' ,
	subtree2: {
		g : 6 ,
		h : [] ,
		i : 'iii',
		p : true ,
		q : [4,5,6] ,
		r : '2'
	} ,
	j : 'Djay' ,
	k : 'ok' ,
	o : 'mg'
} ) ;

with the 'proto' option and a null (or falsy) target, it should create and return a new Object with the prototype of the source Object.

var e , o , proto ;

proto = {
	proto1: 'proto1' ,
	proto2: 'proto2' ,
	hello: function() { console.log( "Hello!" ) ; }
} ;

o = Object.create( proto ) ;
o.own1 = 'own1' ;
o.own2 = 'own2' ;

e = tree.extend( { proto: true } , null , o ) ;

expect( e ).not.to.be( o ) ;
expect( e.__proto__ ).to.equal( proto ) ;	// jshint ignore:line
expect( e ).to.eql( { own1: 'own1' , own2: 'own2' } ) ;
expect( e.proto1 ).to.be( 'proto1' ) ;
expect( e.proto2 ).to.be( 'proto2' ) ;
expect( typeof e.hello ).to.equal( 'function' ) ;

with the 'proto' option should change the prototype of each target properties for the prototype of the related source properties, if 'deep' is enabled it does so recursively.

var e , o , proto1 , proto2 ;

proto1 = {
	proto1: 'proto1' ,
	hello: function() { console.log( "Hello!" ) ; }
} ;

proto2 = {
	proto2: 'proto2' ,
	world: function() { console.log( "World!" ) ; }
} ;

o = {
	own1: 'own1' ,
	own2: 'own2' ,
	embed1: Object.create( proto1 , { a: { value: 'a' , enumerable: true } } ) ,
	embed2: Object.create( proto2 , { b: { value: 'b' , enumerable: true } } )
} ;

e = tree.extend( { proto: true } , {} , o ) ;

expect( e ).not.to.be( o ) ;
expect( e ).to.eql( {
	own1: 'own1' ,
	own2: 'own2' ,
	embed1: { a: 'a' } ,
	embed2: { b: 'b' }
} ) ;
expect( e.embed1 ).to.be( o.embed1 ) ;
expect( e.embed2 ).to.be( o.embed2 ) ;
expect( e.embed1.proto1 ).to.be( 'proto1' ) ;
expect( e.embed2.proto2 ).to.be( 'proto2' ) ;
expect( typeof e.embed1.hello ).to.equal( 'function' ) ;
expect( typeof e.embed2.world ).to.equal( 'function' ) ;


e = tree.extend( { proto: true, deep: true } , {} , o ) ;

expect( e ).not.to.be( o ) ;
expect( e ).to.eql( {
	own1: 'own1' ,
	own2: 'own2' ,
	embed1: { a: 'a' } ,
	embed2: { b: 'b' }
} ) ;
expect( e.embed1 ).not.to.be( o.embed1 ) ;
expect( e.embed2 ).not.to.be( o.embed2 ) ;
expect( e.embed1.proto1 ).to.be( 'proto1' ) ;
expect( e.embed2.proto2 ).to.be( 'proto2' ) ;
expect( typeof e.embed1.hello ).to.equal( 'function' ) ;
expect( typeof e.embed2.world ).to.equal( 'function' ) ;

with 'nofunc' option should skip function.

var e , o , proto ;

proto = {
	proto1: 'proto1' ,
	proto2: 'proto2' ,
	hello: function() { console.log( "Hello..." ) ; }
} ;

o = Object.create( proto ) ;
o.own1 = 'own1' ;
o.world = function() { console.log( "world!!!" ) ; } ;
o.own2 = 'own2' ;

// default behaviour
e = tree.extend( { nofunc: true } , null , o ) ;
expect( e ).not.to.be( o ) ;
expect( e ).to.eql( { own1: 'own1' , own2: 'own2' , proto1: 'proto1' , proto2: 'proto2' } ) ;

// with 'own'
e = tree.extend( { nofunc: true , own: true } , null , o ) ;
expect( e ).not.to.be( o ) ;
expect( e ).to.eql( { own1: 'own1' , own2: 'own2' } ) ;

// with 'proto', function exists if there are in the prototype
e = tree.extend( { nofunc: true , proto: true } , null , o ) ;
expect( e ).not.to.be( o ) ;
expect( e.__proto__ ).to.equal( proto ) ;	// jshint ignore:line
expect( e ).to.eql( { own1: 'own1' , own2: 'own2' } ) ;
expect( e.proto1 ).to.be( 'proto1' ) ;
expect( e.proto2 ).to.be( 'proto2' ) ;
expect( typeof e.hello ).to.equal( 'function' ) ;

with 'preserve' option should not overwrite existing properties in the target.

var e , o ;

e = {
	one: '1' ,
	two: 2 ,
	three: 'THREE'
} ;

o = {
	three: 3 ,
	four: '4'
} ;

tree.extend( { preserve: true } , e , o ) ;
expect( e ).to.eql( { one: '1' , two: 2 , three: 'THREE' , four: '4' } ) ;
expect( o ).to.eql( { three: 3 , four: '4' } ) ;

with 'move' option should move source properties to target properties, i.e. delete them form the source.

var e , o ;

e = {
	one: '1' ,
	two: 2 ,
	three: 'THREE'
} ;

o = {
	three: 3 ,
	four: '4'
} ;

tree.extend( { move: true } , e , o ) ;
expect( e ).to.eql( { one: '1' , two: 2 , three: 3 , four: '4' } ) ;
expect( o ).to.eql( {} ) ;

with 'preserve' and 'move' option should not overwrite existing properties in the target, so it should not move/delete them from the source object.

var e , o ;

e = {
	one: '1' ,
	two: 2 ,
	three: 'THREE'
} ;

o = {
	three: 3 ,
	four: '4'
} ;

tree.extend( { preserve: true , move: true } , e , o ) ;
expect( e ).to.eql( { one: '1' , two: 2 , three: 'THREE' , four: '4' } ) ;
expect( o ).to.eql( { three: 3 } ) ;

with 'inherit' option should inherit rather than extend: each source property create a new Object or mutate existing Object into the related target property, using itself as the prototype.

var e , o ;

o = {
	three: 3 ,
	four: '4' ,
	subtree: {
		five: 'FIVE' ,
		six: 6
	}
} ;

e = {} ;

tree.extend( { inherit: true } , e , o ) ;

expect( e.__proto__ ).to.equal( o ) ;	// jshint ignore:line
expect( e ).to.eql( {} ) ;
expect( e.three ).to.be( 3 ) ;
expect( e.four ).to.be( '4' ) ;
expect( e.subtree ).to.equal( o.subtree ) ;


e = {
	one: '1' ,
	two: 2 ,
	three: 'THREE' ,
} ;

tree.extend( { inherit: true } , e , o ) ;

expect( e.__proto__ ).to.equal( o ) ;	// jshint ignore:line
expect( e ).to.eql( { one: '1' , two: 2 , three: 'THREE' } ) ;
expect( e.three ).to.be( 'THREE' ) ;
expect( e.four ).to.be( '4' ) ;
expect( e.subtree ).to.equal( o.subtree ) ;	// jshint ignore:line
expect( e.subtree ).to.eql( { five: 'FIVE' , six: 6 } ) ;


e = {
	one: '1' ,
	two: 2 ,
	three: 'THREE' ,
	subtree: {
		six: 'SIX' ,
		seven: 7
	}
} ;

tree.extend( { inherit: true } , e , o ) ;

expect( e.__proto__ ).to.equal( o ) ;	// jshint ignore:line
expect( e ).to.eql( { one: '1' , two: 2 , three: 'THREE' , subtree: { six: 'SIX' , seven: 7 } } ) ;
expect( e.three ).to.be( 'THREE' ) ;
expect( e.four ).to.be( '4' ) ;
expect( e.subtree ).to.eql( { six: 'SIX' , seven: 7 } ) ;
expect( e.subtree.five ).to.equal( undefined ) ;

with 'inherit' and 'deep' option should inherit recursively.

var e , o ;

o = {
	three: 3 ,
	four: '4' ,
	subtree: {
		five: 'FIVE' ,
		six: 6
	}
} ;

e = {} ;

tree.extend( { inherit: true , deep: true } , e , o ) ;

expect( e.__proto__ ).to.equal( o ) ;	// jshint ignore:line
expect( e ).to.eql( { subtree: {} } ) ;
expect( e.three ).to.be( 3 ) ;
expect( e.four ).to.be( '4' ) ;
expect( e.subtree.__proto__ ).to.equal( o.subtree ) ;	// jshint ignore:line
expect( e.subtree.five ).to.equal( 'FIVE' ) ;
expect( e.subtree.six ).to.equal( 6 ) ;


e = {
	one: '1' ,
	two: 2 ,
	three: 'THREE' ,
} ;

tree.extend( { inherit: true , deep: true } , e , o ) ;

expect( e.__proto__ ).to.equal( o ) ;	// jshint ignore:line
expect( e ).to.eql( { one: '1' , two: 2 , three: 'THREE' , subtree: {} } ) ;
expect( e.three ).to.be( 'THREE' ) ;
expect( e.four ).to.be( '4' ) ;
expect( e.subtree.__proto__ ).to.equal( o.subtree ) ;	// jshint ignore:line
expect( e.subtree ).to.eql( {} ) ;
expect( e.subtree.five ).to.equal( 'FIVE' ) ;
expect( e.subtree.six ).to.equal( 6 ) ;


e = {
	one: '1' ,
	two: 2 ,
	three: 'THREE' ,
	subtree: {
		six: 'SIX' ,
		seven: 7
	}
} ;

tree.extend( { inherit: true , deep: true } , e , o ) ;

expect( e.__proto__ ).to.equal( o ) ;	// jshint ignore:line
expect( e ).to.eql( { one: '1' , two: 2 , three: 'THREE' , subtree: { six: 'SIX' , seven: 7 } } ) ;
expect( e.three ).to.be( 'THREE' ) ;
expect( e.four ).to.be( '4' ) ;
expect( e.subtree.__proto__ ).to.equal( o.subtree ) ;	// jshint ignore:line
expect( e.subtree ).to.eql( { six: 'SIX' , seven: 7 } ) ;
expect( e.subtree.five ).to.equal( 'FIVE' ) ;

with 'flat' option.

var e , o ;

o = {
	three: 3 ,
	four: '4' ,
	subtree: {
		five: 'FIVE' ,
		six: 6 ,
		subsubtree: {
			subsubsubtree: { one: 'ONE' } ,
			seven: 'seven'
		} ,
		emptysubtree: {}
	} ,
	eight: 8 ,
	anothersubtree: {
		nine: '9'
	}
} ;

e = tree.extend( { flat: true } , {} , o ) ;
expect( e ).to.eql( {
	three: 3 ,
	four: '4' ,
	'subtree.five': 'FIVE' ,
	'subtree.six': 6 ,
	'subtree.subsubtree.seven': 'seven' ,
	'subtree.subsubtree.subsubsubtree.one': 'ONE' ,
	eight: 8 ,
	'anothersubtree.nine': '9'
} ) ;

e = tree.extend( { flat: '/' } , {} , o ) ;
expect( e ).to.eql( {
	three: 3 ,
	four: '4' ,
	'subtree/five': 'FIVE' ,
	'subtree/six': 6 ,
	'subtree/subsubtree/seven': 'seven' ,
	'subtree/subsubtree/subsubsubtree/one': 'ONE' ,
	eight: 8 ,
	'anothersubtree/nine': '9'
} ) ;

with 'unflat' option.

var e , o ;

o = {
	three: 3 ,
	four: '4' ,
	'subtree.five': 'FIVE' ,
	'subtree.six': 6 ,
	'subtree.subsubtree.seven': 'seven' ,
	'subtree.subsubtree.subsubsubtree.one': 'ONE' ,
	eight: 8 ,
	'anothersubtree.nine': '9'
} ;

e = tree.extend( { unflat: true } , {} , o ) ;
expect( e ).to.eql( {
	three: 3 ,
	four: '4' ,
	subtree: {
		five: 'FIVE' ,
		six: 6 ,
		subsubtree: {
			subsubsubtree: { one: 'ONE' } ,
			seven: 'seven'
		}
	} ,
	eight: 8 ,
	anothersubtree: {
		nine: '9'
	}
} ) ;

o = {
	three: 3 ,
	four: '4' ,
	'subtree/five': 'FIVE' ,
	'subtree/six': 6 ,
	'subtree/subsubtree/seven': 'seven' ,
	'subtree/subsubtree/subsubsubtree/one': 'ONE' ,
	eight: 8 ,
	'anothersubtree/nine': '9'
} ;

e = tree.extend( { unflat: '/' } , {} , o ) ;
expect( e ).to.eql( {
	three: 3 ,
	four: '4' ,
	subtree: {
		five: 'FIVE' ,
		six: 6 ,
		subsubtree: {
			subsubsubtree: { one: 'ONE' } ,
			seven: 'seven'
		}
	} ,
	eight: 8 ,
	anothersubtree: {
		nine: '9'
	}
} ) ;

with 'deepFilter' option, using blacklist.

var buf = new Buffer( "My buffer" ) ;

var o = {
	one: '1' ,
	buf: buf ,
	subtree: {
		two: 2 ,
		three: 'THREE'
	}
} ;

var e = tree.extend( { deep: true, deepFilter: { blacklist: [ Buffer.prototype ] } } , {} , o ) ;

o.subtree.three = 3 ;
buf[ 0 ] = 'm'.charCodeAt() ;

expect( e.buf ).to.be.a( Buffer ) ;
expect( e.buf.toString() ).to.be( "my buffer" ) ;
expect( e.buf ).to.be( buf ) ;

expect( e ).to.eql( {
	one: '1' ,
	buf: buf ,
	subtree: {
		two: 2 ,
		three: 'THREE'
	}
} ) ;

with 'deepFilter' option, using whitelist.

var buf = new Buffer( "My buffer" ) ;

var o = {
	one: '1' ,
	buf: buf ,
	subtree: {
		two: 2 ,
		three: 'THREE'
	}
} ;

var e = tree.extend( { deep: true, deepFilter: { whitelist: [ Object.prototype ] } } , {} , o ) ;

o.subtree.three = 3 ;
buf[ 0 ] = 'm'.charCodeAt() ;

expect( e.buf ).to.be.a( Buffer ) ;
expect( e.buf.toString() ).to.be( "my buffer" ) ;
expect( e.buf ).to.be( buf ) ;

expect( e ).to.eql( {
	one: '1' ,
	buf: buf ,
	subtree: {
		two: 2 ,
		three: 'THREE'
	}
} ) ;

Diff

should return an array of differences for two objects without nested object.

var a = {
	a: 'a',
	b: 2,
	c: 'three'
} ;

var b = {
	b: 2,
	c: 3,
	d: 'dee'
} ;

var diff = tree.diff( a , b ) ;

//console.log( diff ) ;
expect( diff ).not.to.be( null ) ;
expect( diff ).to.only.have.keys( '.a', '.c', '.d' ) ;

should return an array of differences for two objects with nested objects.

var a = {
	a: 'a',
	b: 2,
	c: 'three',
	sub: {
		e: 5,
		f: 'six',
		subsub: {
			g: 'gee',
			h: 'h'
		}
	},
	suba: {
		j: 'djay'
	}
} ;

var b = {
	b: 2,
	c: 3,
	d: 'dee',
	sub: {
		e: 5,
		f: 6,
		subsub: {
			g: 'gee',
			i: 'I'
		}
	},
	subb: {
		k: 'k'
	}
} ;

var diff = tree.diff( a , b ) ;

//console.log( diff ) ;
expect( diff ).not.to.be( null ) ;
expect( diff ).to.only.have.keys( '.a', '.c', '.d', '.sub.f', '.sub.subsub.h', '.sub.subsub.i', '.suba', '.subb' ) ;

Masks

should apply a simple mask tree to the input tree.

var mask = tree.createMask( {
	int: true,
	float: true,
	attachement: {
		filename: true,
		unexistant: true
	},
	unexistant: true,
	subtree: {
		subtree: true
	}
} ) ;

var output = mask.applyTo( input ) ;

expect( output ).to.eql( {
	int: 12,
	float: 2.47,
	attachement: {
		filename: 'preview.png'
	},
	subtree: {
		subtree: {
			d: 4,
			e: undefined,
			f: 3.14
		}
	}
} ) ;

should apply a mask tree with wildcard '*' to the input tree.

var mask = tree.createMask( {
	'files': {
		'*': {
			size: true,
			unexistant: true
		}
	}
} ) ;

var output = mask.applyTo( input ) ;

expect( output.files ).to.be.an( Object ) ;
expect( output ).to.eql( {
	files: {
		'background.png' : {
			size : '97856'
		} ,
		'header.png' : {
			size : '44193'
		} ,
		'footer.png' : {
			size : '36411'
		}
	}
} ) ;

should apply a mask tree with wildcard '*' to match array in the input tree.

var mask = tree.createMask( {
	'filesArray': {
		'*': {
			name: true,
			size: true,
			unexistant: true
		}
	}
} ) ;

var output = mask.applyTo( input ) ;

expect( output.filesArray ).to.be.an( Array ) ;
expect( output ).to.eql( {
	filesArray: [
		{
			name : 'background.png' ,
			size : '97856'
		} ,
		{
			name : 'header.png' ,
			size : '44193'
		} ,
		{
			name : 'footer.png' ,
			size : '36411'
		}
	]
} ) ;

//console.log( "\n\n\n\n" , output , "\n\n\n\n" ) ;

should apply a mask with a mask's leaf callback to the input tree.

var leaf = function leaf( input , key , argument , path ) {
	//console.log( 'LEAF: ' , input , key , argument , path ) ;
	
	if ( ! input.hasOwnProperty( key ) ) { return new Error( 'not_found' ) ; }
	if ( typeof input[ key ] === 'number' ) { return input[ key ] + argument ; }
	return input[ key ] ;
} ;

var mask = tree.createMask(
	{
		int: 87 ,
		float: 14 ,
		subtree: {
			subtree: {
				f: 0.0016
			}
		} ,
		unexistant: 45
	} ,
	{ leaf: leaf }
) ;

var output = mask.applyTo( input ) ;

expect( output ).to.eql( {
	int: 99,
	float: 16.47,
	subtree: {
		subtree: {
			f: 3.1416
		}
	}
} ) ;

should apply a mask containing other masks to the input tree.

var mask = tree.createMask( {
	int: true,
	float: true,
	attachement: tree.createMask( {
		filename: true,
		unexistant: true
	} ),
	unexistant: true,
	subtree: tree.createMask( {
		subtree: true
	} )
} ) ;

var output = mask.applyTo( input ) ;

expect( output ).to.eql( {
	int: 12,
	float: 2.47,
	attachement: {
		filename: 'preview.png'
	},
	subtree: {
		subtree: {
			d: 4,
			e: undefined,
			f: 3.14
		}
	}
} ) ;

Inverse masks

should apply a simple mask tree to the input tree.

var mask = tree.createInverseMask( {
	a: true,
	subtree: {
		d: true
	},
	subtree2: true
} ) ;

var output = mask.applyTo( input.subtree ) ;

//console.log( output ) ;

expect( output ).to.eql( {
	b: 2,
	subtree: {
		e: undefined,
		f: 3.14
	},
	c: 'plusplus'
} ) ;