# Yahoo! UI Library

### YAHOO Global 2.8.2r1

Yahoo! UI Library > yahoo > YAHOO.lang
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## Class YAHOO.lang

Provides the language utilites and extensions used by the library

### Properties

#### _IEEnumFix - `private static object`

IE will not enumerate native functions in a derived object even if the function was overridden. This is a workaround for specific functions we care about on the Object prototype.

### Methods

#### augment

`static void augment ( r , s , arguments )`
Same as YAHOO.lang.augmentObject, except it only applies prototype properties. This is an alias for augmentProto.

Parameters:
  `r <Function>` the object to receive the augmentation
  `s <Function>` the object that supplies the properties to augment
  `arguments <String*|boolean>` zero or more properties methods to augment the receiver with. If none specified, everything in the supplier will be used unless it would overwrite an existing property in the receiver. if true is specified as the third parameter, all properties will be applied and will overwrite an existing property in the receiver

#### augmentObject

`static void augmentObject ( r , s , arguments )`
Applies all properties in the supplier to the receiver if the receiver does not have these properties yet. Optionally, one or more methods/properties can be specified (as additional parameters). This option will overwrite the property if receiver has it already. If true is passed as the third parameter, all properties will be applied and _will_ overwrite properties in the receiver.

Parameters:
  `r <Function>` the object to receive the augmentation
  `s <Function>` the object that supplies the properties to augment
  `arguments <String*|boolean>` zero or more properties methods to augment the receiver with. If none specified, everything in the supplier will be used unless it would overwrite an existing property in the receiver. If true is specified as the third parameter, all properties will be applied and will overwrite an existing property in the receiver

#### augmentProto

`static void augmentProto ( r , s , arguments )`
Same as YAHOO.lang.augmentObject, except it only applies prototype properties

Parameters:
  `r <Function>` the object to receive the augmentation
  `s <Function>` the object that supplies the properties to augment
  `arguments <String*|boolean>` zero or more properties methods to augment the receiver with. If none specified, everything in the supplier will be used unless it would overwrite an existing property in the receiver. if true is specified as the third parameter, all properties will be applied and will overwrite an existing property in the receiver

#### dump

`String dump ( o , d )`
Returns a simple string representation of the object or array. Other types of objects will be returned unprocessed. Arrays are expected to be indexed. Use object notation for associative arrays.

Parameters:
  `o <Object>` The object to dump
  `d <int>` How deep to recurse child objects, default 3

Returns: `String`
  the dump result

#### extend

`static void extend ( subc , superc , overrides )`
Utility to set up the prototype, constructor and superclass properties to support an inheritance strategy that can chain constructors and methods. Static members will not be inherited.

Parameters:
  `subc <Function>` the object to modify
  `superc <Function>` the object to inherit
  `overrides <Object>` additional properties/methods to add to the subclass prototype. These will override the matching items obtained from the superclass if present.

#### hasOwnProperty

`boolean hasOwnProperty ( o , prop )`
Determines whether or not the property was added to the object instance. Returns false if the property is not present in the object, or was inherited from the prototype. This abstraction is provided to enable hasOwnProperty for Safari 1.3.x. There is a discrepancy between YAHOO.lang.hasOwnProperty and Object.prototype.hasOwnProperty when the property is a primitive added to both the instance AND prototype with the same value:

    var A = function() {};
    A.prototype.foo = 'foo';
    var a = new A();
    a.foo = 'foo';
    alert(a.hasOwnProperty('foo')); // true
    alert(YAHOO.lang.hasOwnProperty(a, 'foo')); // false when using fallback

Parameters:
  `o <any>` The object being testing
  `prop <string>` the name of the property to test

Returns: `boolean`
  the result

#### isArray

`boolean isArray ( o )`
Determines wheather or not the provided object is an array.

Parameters:
  `o <any>` The object being testing

Returns: `boolean`
  the result

#### isBoolean

`boolean isBoolean ( o )`
Determines whether or not the provided object is a boolean

Parameters:
  `o <any>` The object being testing

Returns: `boolean`
  the result

#### isFunction

`boolean isFunction ( o )`
Determines whether or not the provided object is a function. Note: Internet Explorer thinks certain functions are objects: var obj = document.createElement("object"); YAHOO.lang.isFunction(obj.getAttribute) // reports false in IE var input = document.createElement("input"); // append to body YAHOO.lang.isFunction(input.focus) // reports false in IE You will have to implement additional tests if these functions matter to you.

Parameters:
  `o <any>` The object being testing

Returns: `boolean`
  the result

#### isNull

`boolean isNull ( o )`
Determines whether or not the provided object is null

Parameters:
  `o <any>` The object being testing

Returns: `boolean`
  the result

#### isNumber

`boolean isNumber ( o )`
Determines whether or not the provided object is a legal number

Parameters:
  `o <any>` The object being testing

Returns: `boolean`
  the result

#### isObject

`boolean isObject ( o )`
Determines whether or not the provided object is of type object or function

Parameters:
  `o <any>` The object being testing

Returns: `boolean`
  the result

#### isString

`boolean isString ( o )`
Determines whether or not the provided object is a string

Parameters:
  `o <any>` The object being testing

Returns: `boolean`
  the result

#### isUndefined

`boolean isUndefined ( o )`
Determines whether or not the provided object is undefined

Parameters:
  `o <any>` The object being testing

Returns: `boolean`
  the result

#### isValue

`boolean isValue ( o )`
A convenience method for detecting a legitimate non-null value. Returns false for null/undefined/NaN, true for other values, including 0/false/''

Parameters:
  `o <any>` the item to test

Returns: `boolean`
  true if it is not null/undefined/NaN || false

#### later

`later ( when , o , fn , data , periodic )`
Executes the supplied function in the context of the supplied object 'when' milliseconds later. Executes the function a single time unless periodic is set to true.

Parameters:
  `when <int>` the number of milliseconds to wait until the fn is executed
  `o <object>` the context object
  `fn <Function|String>` the function to execute or the name of the method in the 'o' object to execute
  `data <object>` [Array] data that is provided to the function. This accepts either a single item or an array. If an array is provided, the function is executed with one parameter for each array item. If you need to pass a single array parameter, it needs to be wrapped in an array [myarray]
  `periodic <boolean>` if true, executes continuously at supplied interval until canceled

Returns: ``
  a timer object. Call the cancel() method on this object to stop the timer.

#### merge

`merge ( arguments )`
Returns a new object containing all of the properties of all the supplied objects. The properties from later objects will overwrite those in earlier objects.

Parameters:
  `arguments <Object*>` the objects to merge

Returns: ``
  the new merged object

#### substitute

`String substitute ( s , o , f )`
Does variable substitution on a string. It scans through the string looking for expressions enclosed in { } braces. If an expression is found, it is used a key on the object. If there is a space in the key, the first word is used for the key and the rest is provided to an optional function to be used to programatically determine the value (the extra information might be used for this decision). If the value for the key in the object, or what is returned from the function has a string value, number value, or object value, it is substituted for the bracket expression and it repeats. If this value is an object, it uses the Object's toString() if this has been overridden, otherwise it does a shallow dump of the key/value pairs.

Parameters:
  `s <String>` The string that will be modified.
  `o <Object>` An object containing the replacement values
  `f <Function>` An optional function that can be used to process each match. It receives the key, value, and any extra metadata included with the key inside of the braces.

Returns: `String`
  the substituted string

#### trim

`string trim ( s )`
Returns a string without any leading or trailing whitespace. If the input is not a string, the input will be returned untouched.

Parameters:
  `s <string>` the string to trim

Returns: `string`
  the trimmed string

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