CODEWITHSUNDEEP
javascriptarraysfilter
leblaireau
leblaireau

Reputation: 1223

Returning a single value from a filter

I am trying to return a single value from a filter that returns a large object.

return data.filter(subject => subject.id === 1)
   .map((subject) => {
   return subject.total.toString();
    });

I have tried, toString, JSON.parse and a few more but always get it either as a single array value.

[112]

or a string inside the array

["112"]

but not a single returned value

112

Is map the wrong method? How do I return a pure integer or string would do?

Upvotes: 15

Views: 25357

Answers (4)

madalinivascu
madalinivascu

Reputation: 32354

Filter will always return a array to get the first element use pop

return data.filter(subject => subject.id === 1)
   .map((subject) => {
   return subject.total;
    }).pop();

Upvotes: 1

void
void

Reputation: 36703

You just need to pick the first element. This should suffice..

return data.filter(subject => subject.id === 1)[0].total+""

Upvotes: 3

Jeremy Thille
Jeremy Thille

Reputation: 26400

What about

return data
   .filter(subject => subject.id === 1)
   .map(subject => subject.total.toString())[0] // Take the first element of the array :)

Array.map returns an array. If your initial array contains one element, the output array will also contain one element. Just extract it with [0].

Alternatively. find() returns one object :

return data.find(subject => subject.id === 1).total.toString()

Upvotes: 4

hsz
hsz

Reputation: 152284

Instead of filter which returns an array with filtered values, use find:

const subject = data.find(subject => subject.id === 1);
return subject.total.toString();

or shorter:

return data.find(subject => subject.id === 1).total.toString();

Upvotes: 48

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