适用于所有数据类型的递归版本

 /*jshint esversion: 6 */

// nested array for testing
let nestedArray = ["firstlevel", 32, "alsofirst", ["secondlevel", 456,"thirdlevel", ["theinnerinner", 345, {firstName: "Donald", lastName: "Duck"}, "lastinner"]]];

// wrapper function to protect inner variable tempArray from global scope;
function flattenArray(arr) {

  let tempArray = [];

  function flatten(arr) {
    arr.forEach(function(element) {
      Array.isArray(element) ? flatten(element) : tempArray.push(element);     // ternary check that calls flatten() again if element is an array, hereby making flatten() recursive.
    });
  }

  // calling the inner flatten function, and then returning the temporary array
  flatten(arr);
  return tempArray;
}

// example usage:
let flatArray = flattenArray(nestedArray);

适用于所有数据类型的递归版本

 /*jshint esversion: 6 */

// nested array for testing
let nestedArray = ["firstlevel", 32, "alsofirst", ["secondlevel", 456,"thirdlevel", ["theinnerinner", 345, {firstName: "Donald", lastName: "Duck"}, "lastinner"]]];

// wrapper function to protect inner variable tempArray from global scope;
function flattenArray(arr) {

  let tempArray = [];

  function flatten(arr) {
    arr.forEach(function(element) {
      Array.isArray(element) ? flatten(element) : tempArray.push(element);     // ternary check that calls flatten() again if element is an array, hereby making flatten() recursive.
    });
  }

  // calling the inner flatten function, and then returning the temporary array
  flatten(arr);
  return tempArray;
}

// example usage:
let flatArray = flattenArray(nestedArray);

const common = arr.reduce((a, b) => [...a, ...b], [])

如果您的编码环境支持ES6（ES2015），那么您不需要编写任何递归函数或使用map、reduce等数组方法。

一个简单的排列运算符（…）将帮助您将一个数组展平为单个数组

eg:

  const data = [[1, 2, 3], [4, 5],[2]]
  let res = []
  data.forEach(curSet=>{
      res = [...res,...curSet]
  })
  console.log(res) //[1, 2, 3, 4, 5, 2]

最好是以递归的方式执行，这样如果另一个数组中还有另一个，就可以很容易地过滤。。。

const flattenArray = arr =>
  arr.reduce(
    (res, cur) =>
       !Array.isArray(cur) 
       ? res.concat(cur)
       : res.concat(flattenArray(cur)), []);

你可以这样称呼它：

flattenArray([[["Alireza"], "Dezfoolian"], ["is a"], ["developer"], [[1, [2, 3], ["!"]]]);

结果如下：

["Alireza", "Dezfoolian", "is a", "developer", 1, 2, 3, "!"]

看起来这看起来像是一份招聘工作！

处理多层嵌套处理空数组和非数组参数没有突变不依赖现代浏览器功能

代码：

var flatten = function(toFlatten) {
  var isArray = Object.prototype.toString.call(toFlatten) === '[object Array]';

  if (isArray && toFlatten.length > 0) {
    var head = toFlatten[0];
    var tail = toFlatten.slice(1);

    return flatten(head).concat(flatten(tail));
  } else {
    return [].concat(toFlatten);
  }
};

用法：

flatten([1,[2,3],4,[[5,6],7]]);
// Result: [1, 2, 3, 4, 5, 6, 7]