Need help sorting data on date

Question

So I have some data that returns from a request that looks like this:

[{
  subject: 'something',
  email: '[email protected]',
  name: 'Bert',
  priority: '2'
},
{
  subject: 'something else',
  email: '[email protected]',
  name: 'Betty',
  priority: '4'
},
{
  subject: 'another thing',
  email: '[email protected]',
  name: 'Joanne',
  priority: '1'
}];

But of course with a lot more items. So I'm looking to sort these items on 'priority' so the object with 4 comes first in the array. Any idea how to do this in javascript?

...and we need some more answers about `sort()`, so, please, join — Yevhen Horbunkov, May 08 '19 at 11:33
...and the Oscar goes to the most long-winded orator, posting his identical solution 8 minutes after first answer — Yevhen Horbunkov, May 08 '19 at 11:59
[How much research effort is expected of Stack Overflow users?](https://meta.stackoverflow.com/a/261593/3082296) — adiga, May 08 '19 at 12:00

score 0 · Answer 1 · answered May 08 '19 at 11:28

var f =[{
  subject: 'something',
  email: '[email protected]',
  name: 'Bert',
  priority: '2'
},
{
  subject: 'something else',
  email: '[email protected]',
  name: 'Betty',
  priority: '4'
},
{
  subject: 'another thing',
  email: '[email protected]',
  name: 'Joanne',
  priority: '1'
}];

f.sort((a,b) => +b.priority - +a.priority)
console.log(f)

score 0 · Answer 2 · answered May 08 '19 at 11:44

I wrote a generic function to do the sort by a property name as well as ascending and descending order feature.

function sortDataByPropName(data, property, order) {
    if(order === 'asc'){
      data.sort((a, b) =>  a[property] - b[property])
    } else {
      data.sort((a, b) =>  b[property] - a[property])
    }
    return data;
  }

In your case, you can simply call this function like sortDataByPropName(data, 'priority') or if you want change sort order then simply pass third argument like asc default is desc.

score -1 · Answer 3 · answered May 08 '19 at 11:30

Use sort & convert the value of priority from string to number using parseInt.

let data = [{
    subject: 'something',
    email: '[email protected]',
    name: 'Bert',
    priority: '2'
  },
  {
    subject: 'something else',
    email: '[email protected]',
    name: 'Betty',
    priority: '4'
  },
  {
    subject: 'another thing',
    email: '[email protected]',
    name: 'Joanne',
    priority: '1'
  }
];

let sortedDt = data.sort(function(a, b) {
  return parseInt(b.priority, 10) - parseInt(a.priority, 10)
});

console.log(sortedDt)

this works. Do you know perhaps how to apply a secondary filter? — hxwtch, May 08 '19 at 11:53

score -1 · Accepted Answer · answered May 08 '19 at 11:37

In javascript, there is a method known as .sort() in Array which can be used for sorting. This is how it works.

If compareFunction(a, b) is less than 0, sort a to an index lower than b (i.e. a comes first).
If compareFunction(a, b) returns 0, leave a and b unchanged with respect to each other, but sorted with respect to all different elements. Note: the ECMAScript standard does not guarantee this behaviour, thus, not all browsers (e.g. Mozilla versions dating back to at least 2003) respect this.
If compareFunction(a, b) is greater than 0, sort b to an index lower than a (i.e. b comes first).
compareFunction(a, b) must always return the same value when given a specific pair of elements a and b as its two arguments. If inconsistent results are returned, then the sort order is undefined.

So in our case, we need to sort it in descending order. i.e objects with less priority must come at the top. For that, we need to return a number which is less than 0. Which can be done if we subtract the priority of b by priority of a.

In the code:

const items = [{
  subject: 'something',
  email: '[email protected]',
  name: 'Bert',
  priority: '2'
},
{
  subject: 'something else',
  email: '[email protected]',
  name: 'Betty',
  priority: '4'
},
{
  subject: 'another thing',
  email: '[email protected]',
  name: 'Joanne',
  priority: '1'
}];

const sorted = items.sort((a,b) => b.priority - a.priority);

console.log(sorted);

You can learn much more about it here

Need help sorting data on date

4 Answers4