Implementation method of converting HTMLCollection/NodeList/pseudo array into array_javascript skills

Here, objects that meet the following conditions are called pseudo arrays
1, have length attributes
2, store data by index
3, and do not have array push, pop and other methods

such as
1, arguments within the function.
2. Collections (HTMLCollection, NodeList) obtained through document.forms, Form.elements, Select.options, document.getElementsByName(), document.getElementsByTagName(), childNodes/children, etc.
3. Objects with special writing methods, such as

Copy code The code is as follows:

var obj={};
obj[0] = "one";
obj[1] = "two";
obj[2] = "three";
obj.length = 3;

They do not have some methods of arrays such as push, pop, shift, join, etc. Sometimes you need to convert these pseudo arrays into real arrays, so you can use push, pop and other methods. The following is the tool function makeArray

Copy code The code is as follows:

var makeArray = function(obj) {
return Array.prototype.slice.call(obj,0);
}
try{
Array.prototype.slice.call(document.documentElement.childNodes, 0)[0]. nodeType;
}catch(e){
makeArray = function(obj){
var res = [];
for(var i=0,len=obj.length; ires.push(obj[i]);
}
return res;
}
}

The above three pseudo Array

Copy code The code is as follows:

//Define a function fun, and use makeArray internally to Its arguments are converted into arrays
function fun(){
var ary = makeArray(arguments);
alert(ary.constructor );
}
//Call
fun(3 ,5);


//Assume there are multiple paragraph elements p on the page
var els = document.getElementsByTagName("p");
var ary1 = makeArray(els);
alert(ary1.constructor);


//Special js objects (such as jquery objects)
var obj={};
obj[0] = "one" ;
obj[1] = "two";
obj[2] = "three";
obj.length = 3;

var ary2 = makeArray(obj);
alert(ary2.constructor);