dojo 学习日记之数组操作

dojo 对Javascript1.6 的数组操作功能进行了拓展：

clearCache()
every(arr,callback,thisObject) Determines whether or not every item in arr satisfies the condition implemented by callback.
filter(arr,thisObject) Returns a new Array with those items from arr that match the condition implemented by callback.
forEach(arr,thisObject) for every item in arr,callback is invoked.
indexOf(arr,value,fromIndex,findLast) locates the first index of the provided value in the passed array.
lastIndexOf(arr,fromIndex) locates the last index of the provided value in the passed array.
map(arr,thisObject,Ctr) applies callback to each element of arr and returns an Array with the results
some(arr,thisObject) Determines whether or not any item in arr satisfies the condition implemented by callback.

1.every(arr,thisObject); 校验是否数组arr内的所有元素都满足回调函数的条件，是返回true

Parameter	Type	Description
arr	Array \| String	用来迭代的数组. 如果是string，则对string的没资格字符操作
callback	Function \| String	回调函数被触发，三个参数: item,index,and array ，如果条件满足，返回为true
thisObject	Object	可选可能作为回调函数的作用域

// returns false
array.every([1,2,3,4],function(item){ return item>1; });

// returns true
array.every([1,function(item){ return item>0; });

2.filter(arr,thisObject) ; 返回一个满足过滤条件元素组成的数组

Parameter	Type	Description
arr	Array	the array to iterate over.
callback	Function \| String	a function that is invoked with three arguments (item,array). The return of this function is expected to be a boolean which determines whether the passed-in item will be included in the returned array.
thisObject	Object	Optional may be used to scope the call to callback

// Example
// returns [2,4]
array.filter([1,function(item){ return item>1; });

3.forEach(arr,thisObject) 对arr 的每一个元素，触发回调函数

// log out all members of the array:
array.forEach(
[ "thinger","blah","howdy",10 ],function(item){
console.log(item);
}
);

// log out the members and their indexes
array.forEach(
[ "thinger",function(item,idx,arr){
console.log(item,"at index:",idx);
}
);

// use a scoped object member as the callback
 
var obj = {
prefix: "logged via obj.callback:",callback: function(item){
console.log(this.prefix,item);
}
};

// specifying the scope function executes the callback in that scope
array.forEach(
[ "thinger",obj.callback,obj
);

// alternately,we can accomplish the same thing with lang.hitch()
array.forEach(
[ "thinger",lang.hitch(obj,"callback")
);

4.indexOf(arr,findLast) 从fromIndex 起，返回arr数组中第一次出现value的索引值.

Parameter	Type	Description
arr	Array
value	Object
fromIndex	Integer	Optional
findLast	Boolean	Optional Makes indexOf() work like lastIndexOf(). Used internally; not meant for external usage.

5.map(arr,Ctr) 根据回调函数映射数组值

Parameter	Type	Description
arr	Array \| String	the array to iterate on. If a string,operates on individual characters.
callback	Function \| String	a function is invoked with three arguments,(item,array),and returns a value
thisObject	Object	Optional may be used to scope the call to callback
Ctr	undefined

// returns [2,4,5]
array.map([1,function(item){ return item+1 });

6.some(arr,thisObject) 检验数组里是否有满足回调函数条件，有则返回true

Parameter	Type	Description
arr	Array \| String	the array to iterate over. If a string,operates on individual characters.
callback	Function \| String	a function is invoked with three arguments: item,and array and returns true if the condition is met.
thisObject	Object	Optional may be used to scope the call to callback

// is true
array.some([1,function(item){ return item>1; });

// is false
array.some([1,function(item){ return item<1; });

dojo 学习日记 之 数组操作

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