How to get the order number of an object element?

Question

I just want to ask how to get the order number of an object element, like:

{ '411510958020624384': 272216, <- 0
  '482286641982078977': 195951, <- 1
  '469176984086380574': 156025, <- 2
  '560134275538747403': 126684, <- 3
  '389078110571724801': 101750, <- 4
  '593157035499978752': 66255 } <- 5

For example obj['411510958020624384'] will give you 0, obj['560134275538747403'] will give you 3, and...

How can I do that? ~and thx.

Object. It is an unordered collection of properties – Maksym Petrenko Aug 08 '19 at 13:18 — Maksym Petrenko, Aug 08 '19 at 13:18

Jack Bashford · Accepted Answer · 2019-08-08T13:24:38.903

2

You can't do that. Object keys are unordered.

Support was more or less fixed in ECMAScript 2015, but it's still unreliable. It's far, far better to use an array that you sort, or an array of objects like below:

const keys = [{'411510958020624384':272216},{'482286641982078977':195951},{'469176984086380574':156025},{'560134275538747403':126684},{'389078110571724801':101750},{'593157035499978752':66255}];

const getIndex = (arr, key) => keys.findIndex(({ [key]: k }) => k);

console.log(getIndex(keys, "411510958020624384"));

edited Aug 08 '19 at 13:24

answered Aug 08 '19 at 13:18

Jack Bashford

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Actually will be ordered in this case since keys are numeric – charlietfl Aug 08 '19 at 13:19
Yes @charlietfl, but the unordered-ness of objects generally still stands. – Jack Bashford Aug 08 '19 at 13:19
Right...whatever order OP hoped for will get replaced by sort order – charlietfl Aug 08 '19 at 13:20
My node.js version doen't have this function :/ – Aug 08 '19 at 13:35
What function? `getIndex`? – Jack Bashford Aug 08 '19 at 13:35
(node:4855) UnhandledPromiseRejectionWarning: TypeError: obj.findIndex is not a function – Aug 08 '19 at 15:00
nvm, I have an array for that, I will ask another question about it, in json you can easily get the value by string, but not in arrays, so this is a problem. – Aug 08 '19 at 17:00

How to get the order number of an object element?

1 Answers1