array.map() : Return array instead of object (JavaScript)

Question

I'm still a newbie with javascript. I'm facing a problem with mapping an array. I don't know how to return the an array with objects.

This is the initial array:

array1 = [{firstName: "Harry"},
          {lastName: "Potter"}];

When i do array1.map, it returns:

array1 = ["Potter"];

I want to make array1 to be like this after mapping the lastName:

array1 = [{lastName: "Potter"}];

When i do array1.map, it returns: I can't think of any .map callback that would result in that — CertainPerformance
– CertainPerformance, Commented Dec 30, 2019 at 6:09
why does your array look like that in the first place? why not just have both the firstName and lastName keys on one object? — Jhecht
– Jhecht, Commented Dec 30, 2019 at 6:12
Its okay guys. I just solved it by deleting the firstName property for every loop. — DMDJ
– DMDJ, Commented Dec 30, 2019 at 6:17

Tân · Accepted Answer · 2019-12-30 06:10:32Z

2

You can use filter function instead

array1 = [{firstName: "Harry"},
          {lastName: "Potter"}];
          
console.log(array1.filter(x => x.lastName === "Potter"));

answered Dec 30, 2019 at 6:10

Tân

1

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Comments

Saurabh Agrawal · Accepted Answer · 2019-12-30 06:11:21Z

0

As per the docs:

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

It creates new array and returns it.

answered Dec 30, 2019 at 6:11

Saurabh Agrawal

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