Javascript sort array using two keys

Question

Hi am working on a chat application, I want to sort new messages plus keeping the history order according to time.

For example, I have the chat messages in an array like this

[{"user":"a", "msg":"Hi ", "msg_count":1, "unix_time":"1474476800000"}
{"user":"b", "msg":"Hi ", "msg_count":1, "unix_time":"1478776800000"}
{"user":"c", "msg":"Hi ", "msg_count":5, "unix_time":"1479276800000"}
{"user":"d", "msg":"Hi ", "msg_count":1, "unix_time":"1478416800000"}
{"user":"e", "msg":"Hi ", "msg_count":3, "unix_time":"1478476800000"}]

How can I also sort them using the "msg_count" key where all greater values should come on the top but the remaining objects should be sorted with the "unix_time" key.

May be you are looking for this http://stackoverflow.com/questions/6913512/how-to-sort-an-array-of-objects-by-multiple-fields — Nitheesh, Nov 08 '16 at 10:51
@Cerbrus did you even read my question? i have a number and a string property to sort! All these links don't have none of that! — Ceddy Muhoza, Nov 08 '16 at 10:59
@Tuna: The concept is the same, but here's [another example.](http://stackoverflow.com/questions/1129216/sort-array-of-objects-by-string-property-value-in-javascript) — Cerbrus, Nov 08 '16 at 11:01

Pranav C Balan · Accepted Answer · 2016-11-08T11:03:02.693

1

Use Array#sort method with custom compare function.

var data=[{"user":"a", "msg":"Hi ", "msg_count":1, "unix_time":"1474476800000"},
{"user":"b", "msg":"Hi ", "msg_count":1, "unix_time":"1478776800000"},
{"user":"c", "msg":"Hi ", "msg_count":5, "unix_time":"1479276800000"},
{"user":"d", "msg":"Hi ", "msg_count":1, "unix_time":"1478416800000"},
{"user":"e", "msg":"Hi ", "msg_count":3, "unix_time":"1478476800000"}];


data.sort(function(a, b) {
  // return the difference of `msg_count` property to sort based on them
  // if they are equal then sort based on unix_time prop
  return b.msg_count - a.msg_count || 
    b.unix_time - a.unix_time;
})

console.log(data)

edited Nov 08 '16 at 11:03

answered Nov 08 '16 at 10:51

Pranav C Balan

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Nice one, could you please add sorting for the unix_time key as well – Ceddy Muhoza Nov 08 '16 at 11:00
@Tuna: He already has sorting on `unix_time` implemented there. – Cerbrus Nov 08 '16 at 11:02
@Tuna : in which order – Pranav C Balan Nov 08 '16 at 11:02
@Pranav i mean the "unix_time" property of each object in the array – Ceddy Muhoza Nov 08 '16 at 11:02
The Unix_time property is not affected by your function – Ceddy Muhoza Nov 08 '16 at 11:03

Javascript sort array using two keys

1 Answers1