文件：/lib/OpenLayers/BaseTypes.js
说明：这个类简单一些，对String，Number，Function，Array进行了功能上的扩展。
//首先是对String的扩展
OpenLayers.String = {
//判断str是不是以sub开头
startsWith: function(str, sub) {
return (str.indexOf(sub) == 0);
},
//判断str是不是包含sub
contains: function(str, sub) {
return (str.indexOf(sub) != -1);
},
//str去空白符
trim: function(str) {
return str.replace(/^/s/s*/, ’’).replace(//s/s*$/, ’’);
},
//把用横线连接的单词转换成驼峰形式，例如：my-name -> myName
camelize: function(str) {
var oStringList = str.split(’-’);
var camelizedString = oStringList[0];
for (var i=1, len=oStringList.length; i<len; i++) {
var s = oStringList[i];
camelizedString += s.charAt(0).toUpperCase() + s.substring(1);
}
return camelizedString;
},
//对字符串进行format，这个函数在prototype框架中也有。
format: function(template, context, args) {
if(!context) {
context = window;
}
// Example matching:
// str = ${foo.bar}
// match = foo.bar
var replacer = function(str, match) {
var replacement;
// Loop through all subs. Example: ${a.b.c}
// 0 -> replacement = context[a];
// 1 -> replacement = context[a][b];
// 2 -> replacement = context[a][b][c];
var subs = match.split(//.+/);
for (var i=0; i< subs.length; i++) {
if (i == 0) {
replacement = context;
}
replacement = replacement[subs[i]];
}
if(typeof replacement == "function") {
replacement = args ?
replacement.apply(null, args) :
replacement();
}
// If replacement is undefined, return the string ’undefined’.
// This is a workaround for a bugs in browsers not properly
// dealing with non-participating groups in regular expressions:
// http://blog.stevenlevithan.com/archives/npcg-javascript
if (typeof replacement == ’undefined’) {
return ’undefined’;
} else {
return replacement;
}
};
return template.replace(OpenLayers.String.tokenRegEx, replacer);
},
/**
* Property: OpenLayers.String.tokenRegEx
* Used to find tokens in a string.
* Examples: ${a}, ${a.b.c}, ${a-b}, ${5}
*/
tokenRegEx: //$/{([/w.]+?)/}/g,
/**
* Property: OpenLayers.String.numberRegEx
* Used to test strings as numbers.
*/
numberRegEx: /^([+-]?)(?=/d|/./d)/d*(/./d*)?([Ee]([+-]?/d+))?$/,
/**
* APIFunction: OpenLayers.String.isNumeric
* Determine whether a string contains only a numeric value.
*
* Examples:
* (code)
* OpenLayers.String.isNumeric("6.02e23") // true
* OpenLayers.String.isNumeric("12 dozen") // false
* OpenLayers.String.isNumeric("4") // true
* OpenLayers.String.isNumeric(" 4 ") // false
* (end)
*
* Returns:
* {Boolean} String contains only a number.
*/
isNumeric: function(value) {
return OpenLayers.String.numberRegEx.test(value);
},
/**
* APIFunction: numericIf
* Converts a string that appears to be a numeric value into a number.
*
* Returns
* {Number|String} a Number if the passed value is a number, a String
* otherwise.
*/
numericIf: function(value) {
return OpenLayers.String.isNumeric(value) ? parseFloat(value) : value;
}
};
//下面这段代码过时了，意思就是把startsWith绑到String.prototype上去。3.0中估计会删掉，下面还有很多这样的代码，都一样
if (!String.prototype.startsWith) {
/**
* APIMethod: String.startsWith
* *Deprecated*. Whether or not a string starts with another string.
*
* Parameters:
* sStart - {Sring} The string we’re testing for.
*
* Returns:
* {Boolean} Whether or not this string starts with the string passed in.
*/
String.prototype.startsWith = function(sStart) {
OpenLayers.Console.warn(OpenLayers.i18n("methodDeprecated",
{’newMethod’:’OpenLayers.String.startsWith’}));
return OpenLayers.String.startsWith(this, sStart);
};
}
if (!String.prototype.contains) {
/**
* APIMethod: String.contains
* *Deprecated*. Whether or not a string contains another string.
*
* Parameters:
* str - {String} The string that we’re testing for.
*
* Returns:
* {Boolean} Whether or not this string contains with the string passed in.
*/
String.prototype.contains = function(str) {
OpenLayers.Console.warn(OpenLayers.i18n("methodDeprecated",
{’newMethod’:’OpenLayers.String.contains’}));
return OpenLayers.String.contains(this, str);
};
}
if (!String.prototype.trim) {
/**
* APIMethod: String.trim
* *Deprecated*. Removes leading and trailing whitespace characters from a string.
*
* Returns:
* {String} A trimmed version of the string - all leading and
* trailing spaces removed
*/
String.prototype.trim = function() {
OpenLayers.Console.warn(OpenLayers.i18n("methodDeprecated",
{’newMethod’:’OpenLayers.String.trim’}));
return OpenLayers.String.trim(this);
};
}
if (!String.prototype.camelize) {
/**
* APIMethod: String.camelize
* *Deprecated*. Camel-case a hyphenated string.
* Ex. "chicken-head" becomes "chickenHead", and
* "-chicken-head" becomes "ChickenHead".
*
* Returns:
* {String} The string, camelized
*/
String.prototype.camelize = function() {
OpenLayers.Console.warn(OpenLayers.i18n("methodDeprecated",
{’newMethod’:’OpenLayers.String.camelize’}));
return OpenLayers.String.camelize(this);
};
}
//对Number对象的一个扩展
OpenLayers.Number = {
/**
* Property: decimalSeparator
* Decimal separator to use when formatting numbers.
*/
decimalSeparator: ".",
/**
* Property: thousandsSeparator
* Thousands separator to use when formatting numbers.
*/
thousandsSeparator: ",",
/**
* APIFunction: limitSigDigs
* Limit the number of significant digits on a float.
*
* Parameters:
* num - {Float}
* sig - {Integer}
*
* Returns:
* {Float} The number, rounded to the specified number of significant
* digits.
*/
limitSigDigs: function(num, sig) {
var fig = 0;
if (sig > 0) {
fig = parseFloat(num.toPrecision(sig));
}
return fig;
},
/**
* APIFunction: format
* Formats a number for output.
*
* Parameters:
* num - {Float}
* dec - {Integer} Number of decimal places to round to.
* Defaults to 0. Set to null to leave decimal places unchanged.
* tsep - {String} Thousands separator.
* Default is ",".
* dsep - {String} Decimal separator.
* Default is ".".
*
* Returns:
* {String} A string representing the formatted number.
*/
format: function(num, dec, tsep, dsep) {
dec = (typeof dec != "undefined") ? dec : 0;
tsep = (typeof tsep != "undefined") ? tsep :
OpenLayers.Number.thousandsSeparator;
dsep = (typeof dsep != "undefined") ? dsep :
OpenLayers.Number.decimalSeparator;
if (dec != null) {
num = parseFloat(num.toFixed(dec));
}
var parts = num.toString().split(".");
if (parts.length == 1 && dec == null) {
// integer where we do not want to touch the decimals
dec = 0;
}
var integer = parts[0];
if (tsep) {
var thousands = /(-?[0-9]+)([0-9]{3})/;
while(thousands.test(integer)) {
integer = integer.replace(thousands, "$1" + tsep + "$2");
}
}
var str;
if (dec == 0) {
str = integer;
} else {
var rem = parts.length > 1 ? parts[1] : "0";
if (dec != null) {
rem = rem + new Array(dec - rem.length + 1).join("0");
}
str = integer + dsep + rem;
}
return str;
}
};
if (!Number.prototype.limitSigDigs) {
/**
* APIMethod: Number.limitSigDigs
* *Deprecated*. Limit the number of significant digits on an integer. Does *not*
* work with floats!
*
* Parameters:
* sig - {Integer}
*
* Returns:
* {Integer} The number, rounded to the specified number of significant digits.
* If null, 0, or negative value passed in, returns 0
*/
Number.prototype.limitSigDigs = function(sig) {
OpenLayers.Console.warn(OpenLayers.i18n("methodDeprecated",
{’newMethod’:’OpenLayers.Number.limitSigDigs’}));
return OpenLayers.Number.limitSigDigs(this, sig);
};
}
//对Function对象的一个扩展
OpenLayers.Function = {
//这个函数很有用，可以指定函数中的this指针。在prototype框架中有这个函数
bind: function(func, object) {
// create a reference to all arguments past the second one
var args = Array.prototype.slice.apply(arguments, [2]);
return function() {
// Push on any additional arguments from the actual function call.
// These will come after those sent to the bind call.
var newArgs = args.concat(
Array.prototype.slice.apply(arguments, [0])
);
return func.apply(object, newArgs);
};
},
//扩展了一下bind，传参数时给了event对象
bindAsEventListener: function(func, object) {
return function(event) {
return func.call(object, event || window.event);
};
}
};
if (!Function.prototype.bind) {
/**
* APIMethod: Function.bind
* *Deprecated*. Bind a function to an object.
* Method to easily create closures with ’this’ altered.
*
* Parameters:
* object - {Object} the this parameter
*
* Returns:
* {Function} A closure with ’this’ altered to the first
* argument.
*/
Function.prototype.bind = function() {
OpenLayers.Console.warn(OpenLayers.i18n("methodDeprecated",
{’newMethod’:’OpenLayers.Function.bind’}));
// new function takes the same arguments with this function up front
Array.prototype.unshift.apply(arguments, [this]);
return OpenLayers.Function.bind.apply(null, arguments);
};
}
if (!Function.prototype.bindAsEventListener) {
/**
* APIMethod: Function.bindAsEventListener
* *Deprecated*. Bind a function to an object, and configure it to receive the
* event object as first parameter when called.
*
* Parameters:
* object - {Object} A reference to this.
*
* Returns:
* {Function}
*/
Function.prototype.bindAsEventListener = function(object) {
OpenLayers.Console.warn(OpenLayers.i18n("methodDeprecated",
{’newMethod’:’OpenLayers.Function.bindAsEventListener’}));
return OpenLayers.Function.bindAsEventListener(this, object);
};
}
//对Array对象进行了扩展
OpenLayers.Array = {
/**
* APIMethod: filter
* Filter an array. Provides the functionality of the
* Array.prototype.filter extension to the ECMA-262 standard. Where
* available, Array.prototype.filter will be used.
*
* Based on well known example from http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Reference:Objects:Array:filter
*
* Parameters:
* array - {Array} The array to be filtered. This array is not mutated.
* Elements added to this array by the callback will not be visited.
* callback - {Function} A function that is called for each element in
* the array. If this function returns true, the element will be
* included in the return. The function will be called with three
* arguments: the element in the array, the index of that element, and
* the array itself. If the optional caller parameter is specified
* the callback will be called with this set to caller.
* caller - {Object} Optional object to be set as this when the callback
* is called.
*
* Returns:
* {Array} An array of elements from the passed in array for which the
* callback returns true.
*/
filter: function(array, callback, caller) {
var selected = [];
if (Array.prototype.filter) {
selected = array.filter(callback, caller);
} else {
var len = array.length;
if (typeof callback != "function") {
throw new TypeError();
}
for(var i=0; i<len; i++) {
if (i in array) {
var val = array[i];
if (callback.call(caller, val, i, array)) {
selected.push(val);
}
}
}
}
return selected;
}
};
来自:http://www.openlayers.cn/forum.php?mod=viewthread&tid=38&extra=page%3D6
