why forEach() doesn't work in this object loop?

Question

Why forEach doesn't work for the following? I tried it a few times and it always return "unexpected token".

// for loop
for(item in items){
        if (items[item].id===idNum){
            console.log(items[item]);
        }
    }

// the for loop works. 

// forEach()

items.forEach(item=>if(item.id===idNum){console.log(item)})
// this returned error message "unexpected token"

Because you can not forEach an object. This is part of the Array.prototype. You can Object.keys(items).forEach( instead. — Sebastiaan van Arkens
– Sebastiaan van Arkens, Commented Feb 4, 2019 at 16:47
The error comes from an invalid arrow function structure, though. — Teemu
– Teemu, Commented Feb 4, 2019 at 16:49
item=>if(item.id===idNum){console.log(item)} that if is not an expression, you can't use it there. It should be something like (item) => {if ... } — Federico klez Culloca
– Federico klez Culloca, Commented Feb 4, 2019 at 16:50

Code Maniac · Accepted Answer · 2019-02-04 16:51:33Z

4

Arrow functions can have either a "concise body" or the usual "block body".

In a concise body, only an expression is specified, which becomes the implicit return value. In a block body, you must use an explicit return statement

reference :- Arrow function body

Because this syntax is not correct.

items.forEach(item=>if(item.id===idNum){console.log(item)})

You need to use {} here

items.forEach(item=>{
if(item.id===idNum){console.log(item)}
})

edited Feb 4, 2019 at 16:51

answered Feb 4, 2019 at 16:50

Code Maniac

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MarcoS · Accepted Answer · 2019-02-04 16:53:26Z

0

You have to use brackets for function body:

let items = [ {id:1}, {id:2} ];
let idNum = 2;

items.forEach(item => {
  if (item.id === idNum) { console.log(item) }
})

answered Feb 4, 2019 at 16:53

MarcoS

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