Lang Class

• fn

Defined in yui/js/yui-lang.js:45

Available since 3.5.0

Returns true if the given function appears to be implemented in native code, false otherwise. Will always return false -- even in ES5-capable browsers -- if the useNativeES5 YUI config option is set to false.

This isn't guaranteed to be 100% accurate and won't work for anything other than functions, but it can be useful for determining whether a function like Array.prototype.forEach is native or a JS shim provided by another library.

There's a great article by @kangax discussing certain flaws with this technique: http://perfectionkills.com/detecting-built-in-host-methods/

While his points are valid, it's still possible to benefit from this function as long as it's used carefully and sparingly, and in such a way that false negatives have minimal consequences. It's used internally to avoid using potentially broken non-native ES5 shims that have been added to the page by other libraries.

Parameters:

• fn Function

  Function to test.

Returns:

• o

Defined in yui/js/yui-lang.js:76

Determines whether or not the provided item is an array.

Returns false for array-like collections such as the function arguments collection or HTMLElement collections. Use Y.Array.test() if you want to test for an array-like collection.

Parameters:

• o Object

  The object to test.

Returns:

• o

Defined in yui/js/yui-lang.js:92

Determines whether or not the provided item is a boolean.

Parameters:

• o Object

  The object to test.

Returns:

• o

Defined in yui/js/yui-lang.js:103

Determines whether or not the supplied item is a date instance.

Parameters:

• o Object

  The object to test.

Returns:

• o

Defined in yui/js/yui-lang.js:114

Determines whether or not the provided item is a function. Note: Internet Explorer thinks certain functions are objects:

var obj = document.createElement("object");
Y.Lang.isFunction(obj.getAttribute) // reports false in IE
 
var input = document.createElement("input"); // append to body
Y.Lang.isFunction(input.focus) // reports false in IE

You will have to implement additional tests if these functions matter to you.

Parameters:

• o Object

  The object to test.

Returns:

• o

Defined in yui/js/yui-lang.js:142

Determines whether or not the provided item is null.

Parameters:

• o Object

  The object to test.

Returns:

• o

Defined in yui/js/yui-lang.js:153

Determines whether or not the provided item is a legal number.

Parameters:

• o Object

  The object to test.

Returns:

• o
• failfn

Defined in yui/js/yui-lang.js:164

Determines whether or not the provided item is of type object or function. Note that arrays are also objects, so Y.Lang.isObject([]) === true.

Parameters:

• o Object

  The object to test.

• failfn Boolean

  fail if the input is a function.

Returns:

• value

Defined in yui/js/yui-lang.js:181

Determines whether or not the provided value is a regexp.

Parameters:

• value Object

  The value or object to test.

Returns:

• o

Defined in yui/js/yui-lang.js:192

Determines whether or not the provided item is a string.

Parameters:

• o Object

  The object to test.

Returns:

• o

Defined in yui/js/yui-lang.js:203

Determines whether or not the provided item is undefined.

Parameters:

• o Object

  The object to test.

Returns:

• o

Defined in yui/js/yui-lang.js:214

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 Object

  The item to test.

Returns:

Defined in yui/js/yui-lang.js:239

Available since 3.3.0

Returns the current time in milliseconds.

Returns:

• s
• o

Defined in yui/js/yui-lang.js:251

Available since 3.2.0

Performs {placeholder} substitution on a string. The object passed as the second parameter provides values to replace the {placeholder}s. {placeholder} token names must match property names of the object. For example,

var greeting = Y.Lang.sub("Hello, {who}!", { who: "World" });

{placeholder} tokens that are undefined on the object map will be left in tact (leaving unsightly {placeholder}'s in the output string).

Parameters:

• s String

  String to be modified.

• o Object

  Object containing replacement values.

Returns:

• s

Defined in yui/js/yui-lang.js:274

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:

• s

Defined in yui/js/yui-lang.js:292

Returns a string without any leading whitespace.

Parameters:

• s String

  the string to trim.

Returns:

• s

Defined in yui/js/yui-lang.js:305

Returns a string without any trailing whitespace.

Parameters:

• s String

  the string to trim.

Returns:

• o

Defined in yui/js/yui-lang.js:318

Returns one of the following strings, representing the type of the item passed in:

• "array"
• "boolean"
• "date"
• "error"
• "function"
• "null"
• "number"
• "object"
• "regexp"
• "string"
• "undefined"

Known issues:

• typeof HTMLElementCollection returns function in Safari, but Y.Lang.type() reports "object", which could be a good thing -- but it actually caused the logic in Y.Lang.isObject to fail.

Parameters:

• o Object

  the item to test.

Returns: