如何从数组中的数据在对象中创建键？

Question

How to create the key in an object from data inside an array?

 function createIt(data) { var obj = {}; for (i of data) { obj["fruit"] = i; } return [obj]; } var list = ["orange", "apple", "pineapple"]; console.log(createIt(list)); 

on my code above, the obj.fruit only show the one value, I want to create something like this:

 [ { fruit: "orange" }, { fruit: "apple" }, { fruit: "pineapple" } ] 

Answer 1

Map the input array and get back an array of objects with the key fruit

 var list = ["orange", "apple", "pineapple"]; console.log(list.map(i => ({ fruit: i }))); 

Here a for loop returning a new array, even if I have no idea why you don't want to use map method of arrays:

 const list = ["orange", "apple", "banana"]; const newList = []; for (let i = 0; i < list.length; i++) { newList.push({ fruit: list[i] }); } console.log(newList); 

Here a for loop changing the input array, even if again, no idea why you can't use map method of arrays:

 const list = ['orange', 'banana', 'apple']; for (let i = 0; i < list.length; i++) { list.splice(i, 1, { fruit: list[i] }); } console.log(list); 

Back to your original code:

function createIt(data){
  var obj = {};
  for(i of data){
    obj["fruit"]= i
  }
  return [obj]
}
var list = ["orange", "apple", "pineapple"];
console.log(createIt(list))

You do create a single object, and you always override the value of the fruit key. You should create an array, push the objects into the array in the loop, and then return the array, as below:

 function createIt(data) { var objs = []; for (i of data) { objs.push({fruit: i}); } return objs; } var list = ["orange", "apple", "pineapple"]; console.log(createIt(list)) 

Answer 2

To fix your original code, you should define an initial array, rather than an object, and push an object to that array on each iteration:

 function createIt(data) { const obj = []; for (const i of data) { obj.push({ fruit: i }); } return obj; } var list = ["orange", "apple", "pineapple"]; console.log(createIt(list)) 

That said, .map is much more appropriate when creating a new array based on every item from another array.

 const createIt = data => data.map(fruit => ({ fruit })); var list = ["orange", "apple", "pineapple"]; console.log(createIt(list)) 

Answer 3

You need an array. Create the object inside the loop and push the created object to the array in each iteration. Finally return that array:

 function createIt(data){ var arr = []; for(i of data){ var obj = {}; obj["fruit"]= i; arr.push(obj); } return arr } var list = ["orange", "apple", "pineapple"]; console.log(createIt(list)) 

Though you can shorten your code using Array.prototype.map() :

The map() method creates a new array with the results of calling a provided function on every element in the calling array.

 function createIt(data){ return data.map(d => ({fruit: d})); } var list = ["orange", "apple", "pineapple"]; console.log(createIt(list)) 

Answer 4

You can simply use .map() to get the desired output:

 let list = ["orange", "apple", "pineapple"]; let result = list.map(k => ({fruit: k})); console.log(result); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

Answer 5

Just push the object into the array and return it!

 'use strict'; function createIt(data) { let res = []; for (const i of data) { res.push({ fruit: i }); } return res; } var list = ["orange", "apple", "pineapple"]; console.log(createIt(list));