How to sort an array of objects by multiple fields?

Question

From this original question, how would I apply a sort on multiple fields?

Using this slightly adapted structure, how would I sort city (ascending) & then price (

Answer 1

for a non-generic, simple solution to your exact problem:

homes.sort(
   function(a, b) {          
      if (a.city === b.city) {
         // Price is only important when cities are the same
         return b.price - a.price;
      }
      return a.city > b.city ? 1 : -1;
   });

Answer 2

Wow, there are some complex solutions here. So complex I decided to come up with something simpler but also quite powerful. Here it is;

function sortByPriority(data, priorities) {
  if (priorities.length == 0) {
    return data;
  }

  const nextPriority = priorities[0];
  const remainingPriorities = priorities.slice(1);

  const matched = data.filter(item => item.hasOwnProperty(nextPriority));
  const remainingData = data.filter(item => !item.hasOwnProperty(nextPriority));

  return sortByPriority(matched, remainingPriorities)
    .sort((a, b) => (a[nextPriority] > b[nextPriority]) ? 1 : -1)
    .concat(sortByPriority(remainingData, remainingPriorities));
}

And here is an example of how you use it.

const data = [
  { id: 1,                         mediumPriority: 'bbb', lowestPriority: 'ggg' },
  { id: 2, highestPriority: 'bbb', mediumPriority: 'ccc', lowestPriority: 'ggg' },
  { id: 3,                         mediumPriority: 'aaa', lowestPriority: 'ggg' },
];

const priorities = [
  'highestPriority',
  'mediumPriority',
  'lowestPriority'
];


const sorted = sortByPriority(data, priorities);

This will first sort by the precedence of the attributes, then by the value of the attributes.

Answer 3

Here's an extensible way to sort by multiple fields.

homes.sort(function(left, right) {
    var city_order = left.city.localeCompare(right.city);
    var price_order = parseInt(left.price) - parseInt(right.price);
    return city_order || -price_order;
});

Notes

• a.localeCompare(b) is universally supported and returns -1,0,1 if a<b,a==b,a>b respectively.
• Subtraction works on numeric fields.
• || in the last line gives city priority over price.
• Negate to reverse order in any field, as in -price_order
• Date comparison, var date_order = new Date(left.date) - new Date(right.date); works like numerics because date math turns into milliseconds since 1970.
• Add fields into the or-chain, return city_order || -price_order || date_order;

Answer 4

Sorting on two date fields and a numeric field example:

var generic_date =  new Date(2070, 1, 1);
checkDate = function(date) {
  return Date.parse(date) ? new Date(date): generic_date;
}

function sortData() {  
  data.sort(function(a,b){
    var deltaEnd = checkDate(b.end) - checkDate(a.end);
    if(deltaEnd) return deltaEnd;

    var deltaRank = a.rank - b.rank;
    if (deltaRank) return deltaRank;

    var deltaStart = checkDate(b.start) - checkDate(a.start);
    if(deltaStart) return deltaStart;

    return 0;
  });
}

http://jsfiddle.net/hcWgf/57/

Answer 5

Simplest Way to sort array of object by multiple fields:

 let homes = [ {"h_id":"3",
   "city":"Dallas",
   "state":"TX",
   "zip":"75201",
   "price":"162500"},
  {"h_id":"4",
   "city":"Bevery Hills",
   "state":"CA",
   "zip":"90210",
   "price":"319250"},
  {"h_id":"6",
   "city":"Dallas",
   "state":"TX",
   "zip":"75000",
   "price":"556699"},
  {"h_id":"5",
   "city":"New York",
   "state":"NY",
   "zip":"00010",
   "price":"962500"}
  ];

homes.sort((a, b) => (a.city > b.city) ? 1 : -1);

Output: "Bevery Hills" "Dallas" "Dallas" "Dallas" "New York"

Answer 6

Here's a generic multidimensional sort, allowing for reversing and/or mapping on each level.

Written in Typescript. For Javascript, check out this JSFiddle

The Code

type itemMap = (n: any) => any;

interface SortConfig<T> {
  key: keyof T;
  reverse?: boolean;
  map?: itemMap;
}

export function byObjectValues<T extends object>(keys: ((keyof T) | SortConfig<T>)[]): (a: T, b: T) => 0 | 1 | -1 {
  return function(a: T, b: T) {
    const firstKey: keyof T | SortConfig<T> = keys[0];
    const isSimple = typeof firstKey === 'string';
    const key: keyof T = isSimple ? (firstKey as keyof T) : (firstKey as SortConfig<T>).key;
    const reverse: boolean = isSimple ? false : !!(firstKey as SortConfig<T>).reverse;
    const map: itemMap | null = isSimple ? null : (firstKey as SortConfig<T>).map || null;

    const valA = map ? map(a[key]) : a[key];
    const valB = map ? map(b[key]) : b[key];
    if (valA === valB) {
      if (keys.length === 1) {
        return 0;
      }
      return byObjectValues<T>(keys.slice(1))(a, b);
    }
    if (reverse) {
      return valA > valB ? -1 : 1;
    }
    return valA > valB ? 1 : -1;
  };
}

Usage Examples

Sorting a people array by last name, then first name:

interface Person {
  firstName: string;
  lastName: string;
}

people.sort(byObjectValues<Person>(['lastName','firstName']));

Sort language codes by their name, not their language code (see map), then by descending version (see reverse).

interface Language {
  code: string;
  version: number;
}

// languageCodeToName(code) is defined elsewhere in code

languageCodes.sort(byObjectValues<Language>([
  {
    key: 'code',
    map(code:string) => languageCodeToName(code),
  },
  {
    key: 'version',
    reverse: true,
  }
]));