Understanding the find() method

Question

I'm wondering why arry.find() is working if I write it like this:

const tour = tours.find(el => el.id === id);

But not if I write the arrow function like that:

const tour = tours.find((el) => {el.id === id});

Can someone explain this? In both cases I give a function as parameter.

Because you didn't return when you use `{}`. – Nenad Vracar Aug 29 '20 at 12:17 — Nenad Vracar, Aug 29 '20 at 12:17

score 2 · Answer 1 · answered Aug 29 '20 at 12:18

2

The first one is a shorted line for:

const tour = tours.find(el => { return el.id === id });

You need to add the return in the second case otherwise you return undefined and filter works only with a truethy return.

answered Aug 29 '20 at 12:18

Sascha

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score 0 · Accepted Answer · answered Aug 29 '20 at 12:20

Because, you need to return either true or false in your callback function. So this is how your code should go(in the second case when you use code blocks):

const tour = tours.find((el) => {return el.id === id});

However, arrow functions have a shorthand, where you do not need to use code blocks if it is a one line statement, and it automatically returns the result of the statement, so you don't need to explicitly use return to return the result of the conditional statement.

Understanding the find() method

2 Answers2