How to use map and find together in Typescript?

Question

I am trying to create an array of all string which has length more than zero.

let sampleArray2:string[] = ["hello","world","angular","typescript"];
let subArray:string[] = sampleArray2
    .map(() => sampleArray2
        .find(val => val.length > 5)
    );
console.log(subArray);

As expected, it is returning [ 'angular', 'angular', 'angular', 'angular' ] I wanted it to print [ 'angular', 'typescript' ]

I am specifically looking for a solution which uses both map and find together to accomplish this. How can I fix this?

Note: Though filter is a straightforward solution, I am trying to see if map and find can be used together to get the desired output.

Why not use `filter` ? For example `sampleArray2.filter(v => v.length > 5)` — Titus, Mar 27 '18 at 12:29
I know filter. I am just seeing if the same thing can be done through find and map. — codingsplash, Mar 27 '18 at 12:32
You can't do that because `map` returns an array that has the same length as the original array. — Titus, Mar 27 '18 at 12:34

score 0 · Answer 1 · answered Mar 27 '18 at 12:29

0

let subArray:string[] = sampleArray2.filter(i => i.length > 5);

see MDN web docs - Array.prototype.filter

answered Mar 27 '18 at 12:29

Riscie

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score 0 · Answer 2 · answered Mar 27 '18 at 12:29

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.find is not what you want - you want .filter.

answered Mar 27 '18 at 12:29

Daniel A. White

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score 0 · Answer 3 · answered Mar 27 '18 at 12:31

0

The problem is that your map() returns 'angular' 5 times.

A correct syntax using filter (and therefore preserving your types) should be :

let subArray:string[]= sampleArray2.filter(val=>val.length>5)

answered Mar 27 '18 at 12:31

Mathieu K.

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score 0 · Answer 4 · answered Mar 27 '18 at 12:31

0

You don't need the function map nor the function find.

Use the function filter.

let sampleArray2 = ["hello", "world", "angular", "typescript"];
let subArray = sampleArray2.filter(val => val.length > 5);

console.log(subArray);

answered Mar 27 '18 at 12:31

Ele

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How to use map and find together in Typescript?

4 Answers4