javascript - 重新排列数组的更直观方式

Question

我正在尝试在 JavaScript 中创建一个函数来重新排列数组的索引。我提出了以下想法，但是使用此方法，我必须为作为方法 reformatArray 的第四个参数给出的数组的每个可能长度创建一个新的 else if 子句。方法中的参数能否以更直观的方式添加？

代码:

function start() {
    var array1 = ["Item 1", "Item 2", "Item 3", "Item 4", "Item 5", "Item 6", "Item 7", "Item 8"];

    reformatArray(array1, 1, 2, [1, 2, 0]);
    //output should be ["Item 1", "Item 3", "Item 4", "Item 2", "Item 4", "Item 5", "Item 6", "Item 7", "Item 8"] 
    //WORKS

    var array2 = ["Item 1", "Item 2", "Item 3", "Item 4", "Item 5", "Item 6", "Item 7", "Item 8"];

    reformatArray(array2, 2, 5, [3, 1, 3, 2]);
    //output should be ["Item 1", "Item 2", "Item 6", "Item 4", "Item 6", "Item 5", "Item 8"] 
    //DOES NOT WORK because array as fourth argument is greater than 3 in length
}

function reformatArray(array, startIndex, numOfIndicesToReplace, newIndicesPositions) {
    var newPosLength = newIndicesPositions.length;

    if (newPosLength == 0) {
        array.splice(startIndex, numOfIndicesToReplace);
    } else if (newPosLength == 1) {
        array.splice(startIndex, numOfIndicesToReplace, array[startIndex + newIndicesPositions[0]]);
    } else if (newPosLength == 2) {
        array.splice(startIndex, numOfIndicesToReplace, array[startIndex + newIndicesPositions[0]], array[startIndex + newIndicesPositions[1]]);
    } else if (newPosLength == 3) {
        array.splice(startIndex, numOfIndicesToReplace, array[startIndex + newIndicesPositions[0]], array[startIndex + newIndicesPositions[1]], array[startIndex + newIndicesPositions[2]]);
    }
    //etc.
}

提前致谢。

Answer 1

您可以创建要传递给拼接的参数列表并使用 Function.prototype.apply将它们传递给拼接。

function reformatArray(array, startIndex, numOfIndicesToReplace, newIndicesPositions) {
  var newPosLength = newIndicesPositions.length;
  var params = [startIndex, numOfIndicesToReplace];

  newIndicesPositions.forEach(function(val, pos) {
    params.push(array[startIndex + newIndicesPositions[pos]])
  });

  array.splice.apply(array, params);
}