How to do .forEach() for object in javascript?

Question

I have a data structure similar to:

var object = {
  name: "a",
  number: "1",
  mission: ['a','b','c']
}

Now I want to update them into the database so I need to walk them.

I tried:

object.forEach(function(value, key, map){
  console.log('value: ' + value + ', key: ' + key + ', map:' + map);
});

And then the console report an error: object.forEach is not a function

`forEach` should be invoked on arrays not with an object. If you try on array of objects , it will work — Sridhar, May 31 '17 at 04:50
In modern JS `Object.entries(object).forEach(([key, value]) => console.log(\`key: ${key}, value: ${value}\`));` With polyfills and transpilers this should run anywhere :p — Jaromanda X, May 31 '17 at 04:55
This is not a very good duplicate, because (1) no answers mention `Object.entries` and (2) it is mainly about chunking. — , May 31 '17 at 05:14
I have no idea what you mean by "flat array in the object and do not output map". `object[key]`, where key is the index of a `for...in` loop, or a `forEach` on `Object.keys`, will return the array as-is. — , May 31 '17 at 05:15
@torazaburo later i realized it was just the console itself has flatten the array — Aero Wang, May 31 '17 at 05:17

Anurag Awasthi · Accepted Answer · 2017-05-31T05:01:25.963

8

Try this,

Object.keys(object).forEach(key=>{
    console.log(key ,object[key]);
})

edited May 31 '17 at 05:01

answered May 31 '17 at 04:50

Anurag Awasthi

1

thanks, how do i output map? also this seems to flat array into string... – Aero Wang May 31 '17 at 04:56
@AeroWang well in`forEach` third argument is actual array itself on which you have called `forEach`. Array is converting into string because we are adding it with a string. – Anurag Awasthi May 31 '17 at 05:00
how to keep it as an array? – Aero Wang May 31 '17 at 05:01

score 0 · Answer 2 · answered May 31 '17 at 04:53

0

You could do it like this.

var object = {
  name: "a",
  number: "1",
  mission: ['a','b','c']
}
for(var key in object) console.log(key, object[key]);

answered May 31 '17 at 04:53

sudo

thanks, how do i output map? also this seems to flat array into string... – Aero Wang May 31 '17 at 04:57

score -1 · Answer 3 · answered May 31 '17 at 04:57

-1

Use this,

 for (var item in object) {
    console.log('value: ' + object['name'] + ', key: ' + object['number'] + ', map:' + object['mission']);
 }

answered May 31 '17 at 04:57

Manav Sharma

no, the key in the object will change, they might not be name, number, and mission – Aero Wang May 31 '17 at 04:58
1

Why are you looping over the keys with `item`, but then not doing anything with it? – May 31 '17 at 05:13

3 Answers3