不使用.flat()展平数组；

Question

如何在不使用flat()的情况下展平数组。1级？

到目前为止，我有这个

function flatten(array) {
  let flattened = [];
  for (let i = 0; i < array.length; i++) {
    const current = array[i];
    for (let j = 0; i < current.length; j++) {
      flattened.push(current[j])
    }
  }
  return flattened
}

console.log(flatten([['foo', 'bar'], ['baz', 'qux']]));
// -> ["foo", "bar", "baz", "qux"]
flatten([[1], [2], 3, 4, [5]]);
// -> [1, 2, 3, 4, 5]
flatten([false, [true, [false]], [true]]);
// -> [false, true, [false], true]
flatten([]);
// -> []

它粉碎了我的记忆

Answer 1

我希望这能帮到你

​

var twoDimension = [[1], [2], 3, 4, [5]];

var plano = twoDimension.reduce((acc, el) => acc.concat(el), []);

console.log(plano);

​

Answer 2

您可以使用Array.reduce和spread syntax

​

function flatten(array) {
  return array.reduce(
    (accumulator, item) => {
      // if `item` is an `array`,
      // use the `spread syntax` to 
      // append items of the array into 
      // the `accumulator` array
      if (Array.isArray(item)) {
        return [...accumulator, ...item];
      }
      // otherwise, return items in the 
      // accumulator plus the new item
      return [...accumulator, item];
    }
  , []); // initial value of `accumulator`
}

console.log(flatten([['foo', 'bar'], ['baz', 'qux']]));
// -> ["foo", "bar", "baz", "qux"]
console.log(flatten([[1], [2], 3, 4, [5]]));
// -> [1, 2, 3, 4, 5]
console.log(flatten([false, [true, [false]], [true]]));
// -> [false, true, [false], true]
console.log(flatten([]));
// -> []

​

参考文献：

• Array.reduce - MDN
• Spread syntax - MDN

Answer 3

您可以使用javascript的reducer作为flat()的替代。

const arr = [1, 2, [3, 4]];

arr.reduce((acc, val) => acc.concat(val), []);
// [1, 2, 3, 4]

或者您可以使用分解语法

const flattened = arr => [].concat(...arr);

有关更多详细信息，请访问Mozilla MDN