具有特定数量的元素后如何清空数组？

Question

I am trying to keep a watch on a array , and when it has 10 elements in it , I want to clear the array. I tried using proxies but I am not able to clear my array. What I am trying to achieve is that, I am trying to push some data into an array from eventlisteners , and when the array length reaches 10 I want to send the data to server and clear the array.

Answer 1

You can do it by overriding push method of the array,

function getArrayWithLimitedLength(length) {
    var array = new Array();

    array.push = function () {
        if (this.length >= length) {
            this.splice(0,this.length)
        }
        return Array.prototype.push.apply(this,arguments);
    }

    return array;
}

Create an array with length 3

var array = getArrayWithLimitedLength(3);

once You add 4th element previous 3 elements will be removed and last element will be added as first element.

You can use this.splice(0,this.length) , this.length = 0 to clear the array

or

while(this.length > 0) {
    this.pop();
}

Example:

array.push(1) // array-> [1]
array.push(2) // array-> [1,2]
array.push(3) // array-> [1,2,3]
array.push(4) // array-> [4]

Answer 2

You could check if the array has 10 elements and then call a function for sending the array. Then empty the array by seting the length to zero.

 function sendArray(array) { console.log(...array); } var array = []; setInterval((i => () => { array.push(i++); if (array.length === 10) { sendArray(array); array.length = 0; } })(0), 100); 

Answer 3

Implement you own myPush method:

 Array.prototype.myPush = function(element, maxLengthBeforeFlush= Infinity) { this.push(element); if (this.length > maxLengthBeforeFlush) { // code to send this to the server this.length = 0; } } var arr = []; 

 <button type="button" id="pushToArr" onclick="arr.myPush('a', 5); console.log(arr);">Click to push to arr[]</button>