lang.md

lang

Language Utilities. Easier inheritance, scope handling, type checks.

clone(val):*

Clone native types like Object, Array, RegExp, Date and primitives.

This method will not clone values that are referenced within val. It will only copy the value reference to the new value. If the value is not a plain object but is an object, it will return the value unchanged.

Example

var a = { foo: 'bar' };
var b = clone(a);
console.log(a === b); // false
console.log(a.foo === b.foo); // true

var c = [1, 2, 3];
var d = clone(b);
console.log(c === d); // false
console.log(c); // [1, 2, 3]

See: deepClone()

createObject(parent, [props]):Object

Create Object using prototypal inheritance and setting custom properties.

Mix between Douglas Crockford Prototypal Inheritance and object/mixIn.

Arguments

1. parent (Object) : Parent Object
2. [props] (Object) : Object properties

Example

var base = {
    trace : function(){
        console.log(this.name);
    }
};

var myObject = createObject(base, {
    name : 'Lorem Ipsum'
});

myObject.trace(); // "Lorem Ipsum"

ctorApply(constructor, args):Object

Do Function.prototype.apply() on a constructor while maintaining prototype chain.

function Person(name, surname) {
    this.name = name;
    this.surname = surname;
}

Person.prototype.walk = function(){
    console.log(this.name +' is walking');
};

var args = ['John', 'Doe'];

// "similar" effect as calling `new Person("John", "Doe")`
var john = ctorApply(Person, args);
john.walk(); // "John is walking"

deepClone(val, [instanceClone]):*

Deep clone native types like Object, Array, RegExp, Date and primitives.

The instanceClone function will be invoked to clone objects that are not "plain" objects (as defined by isPlainObject) if it is provided. If instanceClone is not specified, it will not attempt to clone non-plain objects, and will copy the object reference.

Example

var a = {foo:'bar', obj: {a:1, b:2}};
var b = deepClone(a); // {foo:'bar', obj: {a:1, b:2}}
console.log( a === b ); // false
console.log( a.obj === b.obj ); // false

var c = [1, 2, [3, 4]];
var d = deepClone(c); // [1, 2, [3, 4]]
var e = c.concat(); // [1, 2, [3, 4]]

console.log( c[2] === d[2] ); // false
// concat doesn't do a deep clone, arrays are passed by reference
console.log( e[2] === d[2] ); // true

function Custom() { }
function cloneCustom(x) { return new Custom(); }
var f = { test: new Custom() };
var g = deepClone(f, cloneCustom);
g.test === f.test // false, since new Custom instance will be created

See: clone()

deepEquals(a, b, [callback]):Boolean

Recursively tests whether two values contains the same keys and values.

callback specifies the equality comparison function used to compare non-object values. It defaults to using the is() function.

If the values are both an object or array, it will recurse into both values, checking if their keys/values are equal. It will only check the keys and values contained by the objects; it will not check the objects' prototypes. If either of the values are not objects, they will be checked using the callback function.

Example:

deepEquals({ a: 1 }, { a: 1 }); // true
deepEquals({ value: { a: 1 } }, { value: { a: 1 } }); // true
deepEquals({ value: { a: 1 } }, { value: { a: 2 } }); // false
deepEquals({ value: { a: 1 } }, { value: { a: 1, b: 2 } }); // false
deepEquals({}, null); // false
deepEquals(null, null); // true
deepEquals(
    { a: { b: 1 } },
    { a: { b: '1' } },
    function(a, b) { return a == b; }); // true

See: object/equals, array/equals

defaults(val, ...defaults):void

Return first value that isn't null or undefined.

function doSomethingAwesome(foo, bar) {
    // default arguments
    foo = defaults(foo, 'lorem');
    bar = defaults(bar, 123);
    // ...
}

GLOBAL:Object

Reference to the global context (window inside a browser, global on node.js). Works on ES3 and ES5 strict-mode.

inheritPrototype(childCtor, parentCtor):Object

Inherit the prototype methods from one constructor into another.

Similar to node.js util/inherits.

It returns the the childCtor.prototype for convenience.

function Foo(name){
    this.name = name;
}
Foo.prototype = {
    getName : function(){
        return this.name;
    }
};

function Bar(name){
    Foo.call(this, name);
}
//should be called before calling constructor
var proto = inheritPrototype(Bar, Foo);

// for convenience we return the new prototype object
console.log(proto === Bar.prototype); // true

var myObj = new Bar('lorem ipsum');
myObj.getName(); // "lorem ipsum"

console.log(myObj instanceof Foo); // true

// you also have access to the "super" constructor
console.log(Bar.super_ === Foo); // true

is(x, y):Boolean

Check if both values are identical/egal.

// wtfjs
NaN === NaN; // false
-0 === +0;   // true

is(NaN, NaN); // true
is(-0, +0);   // false
is('a', 'b'); // false

See: isnt()

isnt(x, y):Boolean

Check if both values are not identical/egal.

// wtfjs
NaN === NaN; // false
-0 === +0;   // true

isnt(NaN, NaN); // false
isnt(-0, +0);   // true
isnt('a', 'b'); // true

See: is()

isArguments(val):Boolean

If value is an "Arguments" object.

isArray(val):Boolean

If value is an Array. Uses native ES5 Array.isArray() if available.

isBoolean(val):Boolean

If value is a Boolean.

isDate(val):Boolean

If value is a Date.

isEmpty(val):Boolean

Checks if Array/Object/String is empty.

Will return true for any object that doesn't contain enumerable properties and also to any type of value that isn't considered a collection (boolean, null, undefined, function, etc).

isEmpty('');         // true
isEmpty('bar');      // false
isEmpty([]);         // true
isEmpty([1, 2]);     // false
isEmpty({});         // true
isEmpty({a:1, b:2}); // false
// null, undefined, booleans, numbers are considered as "empty" values
isEmpty(null);       // true
isEmpty(undefined);  // true
isEmpty(123);        // true
isEmpty(true);       // true

isFinite(val):Boolean

Checks if value is Finite.

IMPORTANT: This is not the same as native isFinite, which will return true for values that can be coerced into finite numbers. See http://es5.github.com/#x15.1.2.5.

isFinite(123);      // true
isFinite(Infinity); // false

// this is different than native behavior
isFinite('');   // false
isFinite(true); // false
isFinite([]);   // false
isFinite(null); // false

isFunction(val):Boolean

If value is a Function.

isKind(val, kind):Boolean

If value is of "kind". (used internally by some of the isSomething checks).

Favor the other methods since strings are commonly mistyped and also because some "kinds" can only be accurately checked by using other methods (e.g. Arguments), some of the other checks are also faster.

isKind([1,2], 'Array'); // true
isKind(3, 'Array');     // false
isKind(3, 'Number');    // true

See: kindOf()

isInteger(val):Boolean

Check if value is an integer.

isInteger(123);    // true
isInteger(123.45); // false
isInteger({});     // false
isInteger('foo');  // false
isInteger('123');  // false

isNaN(val):Boolean

Check if value is not a number.

It doesn't coerce value into number before doing the check, giving better results than native isNaN. Returns true for everything besides numeric values.

IMPORTANT: behavior is very different than the native isNaN and way more useful!!! See: http://es5.github.io/#x15.1.2.4

isNaN(123);       // false

isNaN(NaN);       // true
isNaN({});        // true
isNaN(undefined); // true
isNaN([4,5]);     // true

// these are all "false" on native isNaN and main reason why this module exists
isNaN('');    // true
isNaN(null);  // true
isNaN(true);  // true
isNaN(false); // true
isNaN("123"); // true
isNaN([]);    // true
isNaN([5]);   // true

isNull(val):Boolean

If value is null.

isNumber(val):Boolean

If value is a Number.

isObject(val):Boolean

If value is an Object.

isPlainObject(val):Boolean

If the value is an Object created by the Object constructor.

isRegExp(val):Boolean

If value is a RegExp.

isString(val):Boolean

If value is a String.

isUndefined(val):Boolean

If value is undefined.

kindOf(val):String

Gets kind of value (e.g. "String", "Number", "RegExp", "Null", "Date"). Used internally by isKind() and most of the other isSomething checks.

kindOf([1,2]); // "Array"
kindOf('foo'); // "String"
kindOf(3);     // "Number"

See: isKind()

toArray(val):Array

Convert array-like object into Array or wrap value into Array.

toArray({
    "0" : "foo",
    "1" : "bar",
    "length" : 2
});                              // ["foo", "bar"]

function foo(){
    return toArray(arguments);
}
foo("lorem", 123);               // ["lorem", 123]

toArray("lorem ipsum");          // ["lorem ipsum"]
toArray(window);                 // [window]
toArray({foo:"bar", lorem:123}); // [{foo:"bar", lorem:123}]

See: object/values()

toNumber(val):Number

Convert value into number.

// numeric values are typecasted as Number
toNumber('123');     // 123
toNumber(-567);      // -567

// falsy values returns zero
toNumber('');        // 0
toNumber(null);      // 0
toNumber(undefined); // 0
toNumber(false);     // 0

// non-numeric values returns NaN
toNumber('asd');     // NaN
toNumber({});        // NaN
toNumber([]);        // NaN

// Date objects return milliseconds since epoch
toNumber(new Date(1985, 6, 23)); // 490935600000

toString(val):String

Convert any value to its string representation.

Will return an empty string for undefined or null, otherwise will convert the value to its string representation.

// null and undefined are converted into empty strings
toString(null);      // ""
toString(undefined); // ""

toString(1);       // "1"
toString([1,2,3]); // "1,2,3"
toString(false);   // "false"

// uses `val.toString()` to convert value
toString({toString:funtion(){ return 'foo'; }}); // "foo"

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For more usage examples check specs inside /tests folder. Unit tests are the best documentation you can get...