/** * Copies the values of `source` to `array`. * 将“source”的值复制到“array” * @private * @param {Array} source 要从中复制值的数组. * @param {Array} [array=[]] 要将值复制到的数组. * @returns {Array} 返回数组. */ function copyArray(source, array) { let index = -1 const length = source.length array || (array = new Array(length)) while (++index < length) { array[index] = source[index] } return array } export default copyArray