如何在javascript中的不同索引上移动数组的第一个元素[重复]

Question

我的数组是：

var array = ["author", "1", "2", "3", "5", "6"]

我正在尝试通过单击按钮将作者移动到数组的第一个位置，而不是数组的第二个位置和末尾。

Answer 1

您可以关闭索引以与下一个交换并检查交换是否可能。如果不返回数组，则交换元素。

const
    swap = (a, i = 0) => () => {
        if (i + 1 >= a.length) return a;
        [a[i + 1], a[i]] = [a[i], a[i +  1]];
        i++;
        return a;
    };

var array = ["author", "1", "2", "3", "5", "6"],
    s = swap(array);

console.log(...array);
console.log(...s());
console.log(...s());
console.log(...s());
console.log(...s());
console.log(...s());
console.log(...s());

如果您不喜欢解构和分配值，则可以改用splice，它从以下索引扩展拼接数组，长度为一项。

const
    swap = (a, i = 0) => () => {
        a.splice(i, 0, ...a.splice(++i, 1));
        return a;
    };

var array = ["author", "1", "2", "3", "5", "6"],
    s = swap(array);

console.log(...array);
console.log(...s());
console.log(...s());
console.log(...s());
console.log(...s());
console.log(...s());
console.log(...s());

Answer 2

点击按钮获取indexOf作者并在另一个变量中获取下一个索引处的元素。如果数组中的下一个位置不是undefined，则将author 的位置与紧邻的下一个元素互换

var array = ["author", "1", "2", "3", "5", "6"]


function shiftAuthor() {
  // get index of author in the array
  let currPosition = array.indexOf('author');
  // if the index of author +1 is not undefined
  if (array[currPosition + 1] !== undefined) {
    // get the element at the next index of author
    let elemAtNextPos = array[currPosition + 1];
    // interchange their position
    array[currPosition + 1] = 'author'
    array[currPosition] = elemAtNextPos;
  }
  console.log(array)
}

<button type='button' onclick='shiftAuthor()'> Shift Author </button>