File: yui/js/yui-lang.js
/**
* The YUI module contains the components required for building the YUI
* seed file. This includes the script loading mechanism, a simple queue,
* and the core utilities for the library.
* @module yui
* @submodule yui-base
*/
/**
* Provides core language utilites and extensions used throughout YUI.
*
* @class Lang
* @static
*/
var L = Y.Lang || (Y.Lang = {}),
STRING_PROTO = String.prototype,
TOSTRING = Object.prototype.toString,
TYPES = {
'undefined' : 'undefined',
'number' : 'number',
'boolean' : 'boolean',
'string' : 'string',
'[object Function]': 'function',
'[object RegExp]' : 'regexp',
'[object Array]' : 'array',
'[object Date]' : 'date',
'[object Error]' : 'error'
},
SUBREGEX = /\{\s*([^|}]+?)\s*(?:\|([^}]*))?\s*\}/g,
TRIMREGEX = /^\s+|\s+$/g,
NATIVE_FN_REGEX = /\{\s*\[(?:native code|function)\]\s*\}/i;
// -- Protected Methods --------------------------------------------------------
/**
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.
@method _isNative
@param {Function} fn Function to test.
@return {Boolean} `true` if _fn_ appears to be native, `false` otherwise.
@static
@protected
@since 3.5.0
**/
L._isNative = function (fn) {
return !!(Y.config.useNativeES5 && fn && NATIVE_FN_REGEX.test(fn));
};
// -- Public Methods -----------------------------------------------------------
/**
* 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.
*
* @method isArray
* @param o The object to test.
* @return {boolean} true if o is an array.
* @static
*/
L.isArray = L._isNative(Array.isArray) ? Array.isArray : function (o) {
return L.type(o) === 'array';
};
/**
* Determines whether or not the provided item is a boolean.
* @method isBoolean
* @static
* @param o The object to test.
* @return {boolean} true if o is a boolean.
*/
L.isBoolean = function(o) {
return typeof o === 'boolean';
};
/**
* Determines whether or not the supplied item is a date instance.
* @method isDate
* @static
* @param o The object to test.
* @return {boolean} true if o is a date.
*/
L.isDate = function(o) {
return L.type(o) === 'date' && o.toString() !== 'Invalid Date' && !isNaN(o);
};
/**
* <p>
* Determines whether or not the provided item is a function.
* Note: Internet Explorer thinks certain functions are objects:
* </p>
*
* <pre>
* 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
* </pre>
*
* <p>
* You will have to implement additional tests if these functions
* matter to you.
* </p>
*
* @method isFunction
* @static
* @param o The object to test.
* @return {boolean} true if o is a function.
*/
L.isFunction = function(o) {
return L.type(o) === 'function';
};
/**
* Determines whether or not the provided item is null.
* @method isNull
* @static
* @param o The object to test.
* @return {boolean} true if o is null.
*/
L.isNull = function(o) {
return o === null;
};
/**
* Determines whether or not the provided item is a legal number.
* @method isNumber
* @static
* @param o The object to test.
* @return {boolean} true if o is a number.
*/
L.isNumber = function(o) {
return typeof o === 'number' && isFinite(o);
};
/**
* Determines whether or not the provided item is of type object
* or function. Note that arrays are also objects, so
* <code>Y.Lang.isObject([]) === true</code>.
* @method isObject
* @static
* @param o The object to test.
* @param failfn {boolean} fail if the input is a function.
* @return {boolean} true if o is an object.
* @see isPlainObject
*/
L.isObject = function(o, failfn) {
var t = typeof o;
return (o && (t === 'object' ||
(!failfn && (t === 'function' || L.isFunction(o))))) || false;
};
/**
* Determines whether or not the provided item is a string.
* @method isString
* @static
* @param o The object to test.
* @return {boolean} true if o is a string.
*/
L.isString = function(o) {
return typeof o === 'string';
};
/**
* Determines whether or not the provided item is undefined.
* @method isUndefined
* @static
* @param o The object to test.
* @return {boolean} true if o is undefined.
*/
L.isUndefined = function(o) {
return typeof o === 'undefined';
};
/**
* A convenience method for detecting a legitimate non-null value.
* Returns false for null/undefined/NaN, true for other values,
* including 0/false/''
* @method isValue
* @static
* @param o The item to test.
* @return {boolean} true if it is not null/undefined/NaN || false.
*/
L.isValue = function(o) {
var t = L.type(o);
switch (t) {
case 'number':
return isFinite(o);
case 'null': // fallthru
case 'undefined':
return false;
default:
return !!t;
}
};
/**
* Returns the current time in milliseconds.
*
* @method now
* @return {Number} Current time in milliseconds.
* @static
* @since 3.3.0
*/
L.now = Date.now || function () {
return new Date().getTime();
};
/**
* Lightweight version of <code>Y.substitute</code>. Uses the same template
* structure as <code>Y.substitute</code>, but doesn't support recursion,
* auto-object coersion, or formats.
* @method sub
* @param {string} s String to be modified.
* @param {object} o Object containing replacement values.
* @return {string} the substitute result.
* @static
* @since 3.2.0
*/
L.sub = function(s, o) {
return s.replace ? s.replace(SUBREGEX, function (match, key) {
return L.isUndefined(o[key]) ? match : o[key];
}) : s;
};
/**
* Returns a string without any leading or trailing whitespace. If
* the input is not a string, the input will be returned untouched.
* @method trim
* @static
* @param s {string} the string to trim.
* @return {string} the trimmed string.
*/
L.trim = STRING_PROTO.trim ? function(s) {
return s && s.trim ? s.trim() : s;
} : function (s) {
try {
return s.replace(TRIMREGEX, '');
} catch (e) {
return s;
}
};
/**
* Returns a string without any leading whitespace.
* @method trimLeft
* @static
* @param s {string} the string to trim.
* @return {string} the trimmed string.
*/
L.trimLeft = STRING_PROTO.trimLeft ? function (s) {
return s.trimLeft();
} : function (s) {
return s.replace(/^\s+/, '');
};
/**
* Returns a string without any trailing whitespace.
* @method trimRight
* @static
* @param s {string} the string to trim.
* @return {string} the trimmed string.
*/
L.trimRight = STRING_PROTO.trimRight ? function (s) {
return s.trimRight();
} : function (s) {
return s.replace(/\s+$/, '');
};
/**
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 <code>Y.Lang.isObject</code> to fail.
@method type
@param o the item to test.
@return {string} the detected type.
@static
**/
L.type = function(o) {
return TYPES[typeof o] || TYPES[TOSTRING.call(o)] || (o ? 'object' : 'null');
};
