CODEWITHSUNDEEP
javascriptarrayssorting
Luca De Nardi
Luca De Nardi

Reputation: 2321

Sort an array of object by a property (with custom order, not alphabetically)

I would like to get your help about this little problem.

I have like to order this array depending on the code value but not in alphabetical order. (I specified this in bold but got eventually flagged anyway, people don't even care about reading the question)

For example I would like to have all the green objects, then all the blue ones and then all the red ones. What is the best way to do that?

[
    { code: "RED", value: 0},
    { code: "BLUE", value: 0},
    { code: "RED", value: 0},
    { code: "GREEN", value: 0},
    { code: "BLUE", value: 0},
    { code: "RED", value: 0},
    { code: "GREEN", value: 0},
    { code: "BLUE", value: 0}
]

Is it possible to do that with the sort function? What would the condition be in that case?

Upvotes: 4

Views: 4647

Answers (7)

Nina Scholz
Nina Scholz

Reputation: 386540

You could take an object for the wanted order.

var array = [{ code: "RED", value: 0 }, { code: "BLUE", value: 0 }, { code: "RED", value: 0 }, { code: "GREEN", value: 0 }, { code: "BLUE", value: 0 }, { code: "RED", value: 0 }, { code: "GREEN", value: 0 }, { code: "BLUE", value: 0 }],
    order = { GREEN: 1, BLUE: 2, RED: 3 };
    
array.sort(function (a, b) {
    return order[a.code] - order[b.code];
});

console.log(array);
.as-console-wrapper { max-height: 100% !important; top: 0; }

For unknow colors/values, you could use a default value with

  • 0, for sorting to top or
  • Infinity or as some suggest because of the ability for caculating Number.MAX_VALUE for sorting to the end,
  • or any other value for sorting inbetween the other groups.

At last you could sort the special treated items with an other sorting part, chained with logical OR ||.

var array = [{ code: "YELLOW", value: 0 }, { code: "BLACK", value: 0 }, { code: "RED", value: 0 }, { code: "BLUE", value: 0 }, { code: "RED", value: 0 }, { code: "GREEN", value: 0 }, { code: "BLUE", value: 0 }, { code: "RED", value: 0 }, { code: "GREEN", value: 0 }, { code: "BLUE", value: 0 }],
    order = { GREEN: 1, BLUE: 2, RED: 3, default: Infinity };
    
array.sort(function (a, b) {
    return (order[a.code] || order.default) - (order[b.code] || order.default) || a.code.localeCompare(b.code);
});

console.log(array);
.as-console-wrapper { max-height: 100% !important; top: 0; }

Upvotes: 19

Kthree
Kthree

Reputation: 318

You can use the sort function i.e Array.prototype.sort() Visit https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort

Firstly you have to decide whether you want to sort in ascending order or in descending order. To sort in ascending order you can do something like this:

arr.sort((a, b) => {
    return a.color < b.color ? -1 : a.color > b.color ? 1 : 0;
  });

An to do it in descending order:

arr.sort((a, b) => {
    return a.color > b.color ? -1 : a.color < b.color ? 1 : 0;
  });

Now suppose you want a certain color sorted and displayed first. You can have a function like this:

const sortByKeyAsc = (arr,color) =>
  arr.sort((a, b) => {
    if(a.color < b.color || (a.color === color && b.color !== color)){
      return -1;
    }
    if(a.color > b.color || (a.color !== color && b.color === color)){
      return 1
    }
    return 0;
  });

and you can use it like this:

const array1 = sortByKeyAsc(arr,'pink');

Upvotes: 1

Hadi Zare
Hadi Zare

Reputation: 19

this is a function for sorting by a specific color.

const colors = [{
    name: "T-shirt",
    color: "red",
    price: 20
  },
  {
    name: "Shoes",
    color: "yellow",
    price: 20
  },
  {
    name: "Pants",
    color: "red",
    price: 20
  },
  {
    name: "Cap",
    color: "yellow",
    price: 20
  },
  {
    name: "Skirt",
    color: "red",
    price: 15
  },
]

let sortByColor = color => colors.sort((a, b) => a.color === color ? -1 : 1)

console.log(sortByColor('red'))

Upvotes: 1

Bijay Poudel
Bijay Poudel

Reputation: 647

You can sort color alphabetically by using this function

  var sortedArr = arr.sort((first, second)=>{
            
        return first.color < second.color ? -1 : 1
    })

Upvotes: 0

somedirection
somedirection

Reputation: 717

I was dealing with a case where I had to match a string status and sort by the various statuses specifically. .findIndex and .includes ended up being the best approach.

statusPriority sets the intended order. Once the indexes are found they can be compared and returned to the .sort

let records = [
  {status: 'Record is ready to submit.', active: true, name: 'A'},
  {status: 'Record has been sent.', active: true, name: 'B'},
  {status: 'Activation is required.', active: true, name: 'C'},
  {status: 'Record submission failed.', active: true, name: 'D'},
  {status: 'Creation is pending.', active: true, name: 'E'},
]

console.log(records.map(r => r.status))

let statusPriority = ['creation', 'activation', 'sent', 'ready', 'failed'];
records.sort((a, b) => {
  let aIndex = statusPriority.findIndex(status => a.status.toLowerCase().includes(status));
  let bIndex = statusPriority.findIndex(status => b.status.toLowerCase().includes(status));
  return aIndex - bIndex;
})

console.log(records.map(r => r.status))

Upvotes: 0

kind user
kind user

Reputation: 41893

You could implement a schema array and sort according to element's index inside that schema array.

const a = ['GREEN', 'BLUE', 'RED'];

const o = [{code:"RED",value:0},{code:"BLUE",value:0},{code:"RED",value:0},{code:"GREEN",value:0},{code:"BLUE",value:0},{code:"RED",value:0},{code:"GREEN",value:0},{code:"BLUE",value:0}];

const r = o.slice().sort(({ code: q }, { code: w }) => a.indexOf(q) - a.indexOf(w));

console.log(r);

Upvotes: 1

gurvinder372
gurvinder372

Reputation: 68383

Set the custom priority first

var codePriority = [ "GREEN", "BLUE", "RED" ];

Now use the same in sorting as

arr.sort( function(a,b){ 
   if ( a.code == b.code ) return a.value - b.value;
   return codePriority.indexOf( a.code ) - codePriority.indexOf( b.code ) ; notice this line
})

Demo

var arr = [
    { code: "RED", value: 0},
    { code: "BLUE", value: 0},
    { code: "RED", value: 0},
    { code: "GREEN", value: 0},
    { code: "BLUE", value: 0},
    { code: "RED", value: 0},
    { code: "GREEN", value: 0},
    { code: "BLUE", value: 0}
];
var codePriority = [ "GREEN", "BLUE", "RED" ];
arr.sort( function(a,b){ 
   if ( a.code == b.code ) return a.value - b.value;
   return codePriority.indexOf( a.code ) - codePriority.indexOf( b.code )
});
console.log( arr );

Upvotes: 3

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