读源码，学技术 -- 快速删除数组元素

 

 

快速删除数组元素（在不考虑数组顺序的时候）

/**
 * Removes the array item at the specified index.
 * It's faster but the order of the array will be changed.
 * @method fastRemoveAt
 * @param {any[]} array
 * @param {Number} index
 */
function fastRemoveAt (array, index) {
    var length = array.length;
    if (index < 0 || index >= length) {
        return;
    }
    array[index] = array[length - 1];
    array.length = length - 1;
}


/**
 * Removes the first occurrence of a specific object from the array.
 * It's faster but the order of the array will be changed.
 * @method fastRemove
 * @param {any[]} array
 * @param {Number} value
 */
function fastRemove (array, value) {
    var index = array.indexOf(value);
    if (index >= 0) {
        array[index] = array[array.length - 1];
        --array.length;
    }
}