Javascript Array. prototype. slice usage example

Often, we can see Array. prototype. slice (arguments, 0); this method can be used in function () {}, so that the function parameter list can be converted into a real array. Take an example:
Copy codeThe Code is as follows:
Var slice = Array. prototype. slice;
Var toString = Object. prototype. toString;
(Function (){
Var args = arguments;
Console. log (args, toString. call (args); // [1, 2, 3] "[object Arguments]"
Var argsArr = slice (args, 0 );
Console. log (argsArr, toString. call (argsArr); // [1, 2, 3] "[object Array]"
} (1, 2, 3 ))

We can see that the arguments parameter list of the function is changed to Array in one second after being called by slice.
Similarly, you can convert the selected DOM element to an array:
Copy codeThe Code is as follows:
Slice. call (document. querySelectorAll ("div "));

Let's see if the slide method can convert objects into arrays? See the example below:
Copy codeThe Code is as follows:
Console. log (slice. call ('string'); // ["s", "t", "r", "I", "n", "g"]
Console. log (slice. call (new String ('string'); // ["s", "t", "r", "I", "n", "g"]

Each time, the string is directly converted into an array.
However, digits and boolean values are converted into an empty array:
Copy codeThe Code is as follows:
Console. log (slice. call (33 ));
Console. log (slice. call (true ));

A normal object is also converted to an empty array, unless you add a length attribute to it:
Copy codeThe Code is as follows:
Console. log (slice. call ({name: 'obj '}); // []
Console. log (slice. call ({0: 'zero ', 1: 'one'}); // []
Console. log (slice. call ({0: 'zero ', 1: 'one', name: 'obj', length: 2}); // ["zero", "one"]

Also, it can be used to clone Arrays:
Copy codeThe Code is as follows:
Var srcArr = [1, 2, 3];
Var newArr = srcArr. slice (0 );
Console. log (srcArr, newArr); // [1, 2, 3] [1, 3]
Console. log (srcArr = newArr); // false