javascript how to avoid numbered object keys to be sorted automatically

Asked Jan 29 '21 at 16:11

Active Jan 29 '21 at 16:13

Viewed 50 times

I have this:

const obj = {};
obj['7'] = {name: '7'};
obj['5'] = {name: '5'};
obj['3'] = {name: '3'};

console.log(obj);

The expected output is:

{ 
   '7' : { name: '7'}, 
   '5' : { name: '5'}, 
   '3' : { name: '3'}
}

But instead, I got:

{ 
   '3' : { name: '3'}, 
   '5' : { name: '5'}, 
   '7' : { name: '7'}
}

How can I overcome this?

edited Jan 29 '21 at 16:13

Letsintegreat

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asked Jan 29 '21 at 16:11

assembler

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1

You cannot. The specs define the ordering of positive integer keys to be in ascending order. You should instead be using a different way to keep the order, if it's important. – VLAZ Jan 29 '21 at 16:12
@VLAZ, yes, the order is important. thanks for the tip... – assembler Jan 29 '21 at 16:13
3

Use a `Map` instead. Maps preserve insertion order. Objects don't. – Niet the Dark Absol Jan 29 '21 at 16:13
@VLAZ can you provide some clear example? – Jan 29 '21 at 16:13
3

why not take an array? – Nina Scholz Jan 29 '21 at 16:14
@alex clear example of the spec or a data structure? – VLAZ Jan 29 '21 at 16:14
@NinaScholz, it has to be an object... I wish it would be an array – assembler Jan 29 '21 at 16:15
You can likely use an array or, if you need an object, provide a change to symbol.iterator to return the values in a specific order – zfrisch Jan 29 '21 at 16:16
An array *is* an object. – trincot Jan 29 '21 at 16:16
@trincot everything is an object. I think the understanding is that we're all referring to the object type. – zfrisch Jan 29 '21 at 16:17
1

@zfrisch, *"everything is an object"*: no. *"referring to the object type"*: `typeof [] === "object"` – trincot Jan 29 '21 at 16:18
Related: [Does ES6 introduce a well-defined order of enumeration for object properties?](https://stackoverflow.com/q/30076219) – VLAZ Jan 29 '21 at 16:19
... what? What are you arguing for. Saying that an Array is an object doesn't really pertain to what the user was saying in context. – zfrisch Jan 29 '21 at 16:23

javascript how to avoid numbered object keys to be sorted automatically

0 Answers0