Question

我有一个看起来像这样的数组

var myArray = [
    ['a', 1],
    ['b', 2],
    ['c', 3]
]

我想将它转换为一个对象，它应该等于下面：

var myObj = {
    'a' : 1,
    'b' : 2,
    'c' : 3
}

什么是更容易和更安全的（如果出现意外输入）的方式呢？

更新：为了详细说明“更安全”，有时我可能会得到不同的输入，如

var myArray = [
    ['a', 1],
    ['b', 2],
    ['c', 3, 4, 5]
]

或

var myArray = [
    ['a', 1],
    ['b', 2],
    ['c', 3],
    ['d']
]

无论myObj应该等于：

var myObj = {
    'first-key' : 'firts-value'
}

或者第二个元素在子数组中不可用

var myObj = {
    'first-key' : ''
}

Answer 1

您可以使用reduce()

执行此操作

var myArray = [
  ['a', 1],
  ['b', 2],
  ['c', 3]
]

var result = myArray.reduce((r, e) => {
  r[e[0]] = e[1];
  return r;
} , {});

console.log(result)

更新：对于数组中只有一个元素（返回''）或多于两个元素的情况（返回包含其余元素的数组）。

var myArray = [
  ['a', 1],
  ['b', 2],
  ['c', 3, 3 ,1],
  ['d']
]

var result = myArray.reduce((r, e) => {
  r[e[0]] = (e[1]) ? ((e.length > 2) ? e.slice(1) : e[1]) : '';
  return r;
} , {});

console.log(result)

Answer 2

var myArray = [
    ['a', 1],
    ['b', 2],
    ['c', 3]
];

var myObj = {};

myArray.forEach(function(element){
    myObj[element[0]] = element[1];
})

Answer 3

只需使用forEach填充myObj：

＆＃13;

var myArray = [
    ['a', 1],
    ['b', 2],
    ['c', 3]
];
var myObj = {};
myArray.forEach(x => myObj[x[0]]=x[1]);
console.log(myObj);

＆＃13;

Answer 4

其他答案都没有处理意外输入......执行此操作的方法是使用.reduce()和类型检查。

var myArray = [
  [[1, 2, 3], 'a'], // [1] is valid property name, [0] valid value
  ['b', 2, 5, 2], // [0] is valid property name, [1] valid value
  ['c', undefined], // [0] is valid property name, [1] invalid value
  { prop1: "123" }, // Invalid - is not an array
  undefined, // Invalid - is not an array
  123, // Invalid - is not an array
  [undefined, 'd'], // [1] is valid property name, [0] valid value
  ['e'] // [0] is valid property name, [1] does not exist
];

function convertArrToObj(arr) {
  // check to ensure that parent is actually an array
  if (isArray(arr)) {
    return arr.reduce(function(obj, curr) {
      // check to ensure each child is an array with length > 0
      if (isArray(curr) && curr.length > 0) {
        // if array.length > 1, we are interested in [0] and [1]
        if (curr.length > 1) {
          // check if [0] is valid property name
          if (typeof curr[0] === "string" || typeof curr[0] === "number") {
            // if so, use [0] as key, and [1] as value
            obj[curr[0]] = curr[1] || ""
          } 
          // if not, check if [1] is a valid property name
          else if (typeof curr[1] === "string" || typeof curr[1] === "number") {
            // if so, use [1] as key, and [0] as value
            obj[curr[1]] = curr[0] || ""
          }
          // if no valid property names found, do nothing
        } else {
          // if array.length === 1, check if the one element is
          // a valid property name. 
          if (typeof curr[0] === "string" || typeof curr[0] === "number") {
            // If so, add it and use "" as value
            obj[curr[0]] = "";
          }
        }
      }
      // return updated object for next iteration
      return obj
    }, {});
  }
}

function isArray(val) {
  return val === Object(val) && Object.prototype.toString.call(val) === '[object Array]';
}

console.log(convertArrToObj(myArray));

Javascript / Node.js：将带有子数组的数组转换为对象

4 个答案: