How to create an object using map function?

Question

I want to create an array for my app's dropdown list for age selection. However I dont want to type all ages from 10 till 80. I can create an array with for loop and push methods but I couldn't create format for dropdown list.

You can find below array format below.

const ageData = [{ value: 10 }, { value: 11 }, { value: 12 }];

score 1 · Accepted Answer · answered Jan 18 '19 at 14:09

1

Using map() as requested:

const ageData = [...Array(71)].map((x, i) => ({value: i + 10}));
console.log(ageData);

First, create an array with length 71. Destructure the array, giving [undefined, undefined, ..., undefined]. Then, using map(), iterate through the array and return the index, plus 10.

answered Jan 18 '19 at 14:09

Chris

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Thanks Chris for your quick response – sinan Jan 18 '19 at 14:48

score 1 · Answer 2 · answered Jan 18 '19 at 14:09

1

You can use Array.from():

const ageData = Array.from(
    {length: 71}, (_, i) => ({value: i + 10})
);

console.log(ageData);

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

answered Jan 18 '19 at 14:09

Mohammad Usman

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1

OP is asking to use `map()` function specifically. – Chris Jan 18 '19 at 14:13
@Chris `.map()` doesn't operate on blank array or array with undefined values directly. We need to offer other alternatives. – Mohammad Usman Jan 18 '19 at 14:17
It does not operate on a blank array, but it does on undefined values. Check my answer – Chris Jan 18 '19 at 14:22

score 0 · Answer 3 · answered Jan 18 '19 at 14:08

const ageData = new Array(70).fill(1).map((_, index) => ({ value: index + 10 }))

Also you can create a helper that generates that type of data in a more generic way

function generateAgeData (from, to) {
  return new Array(to - from).fill(1).map((_, index) => ({
    value: from + index
  }));
}

How to create an object using map function?

3 Answers3