Sort an array based on another array's values

Question

How can I sort this array:

var list = [
    'forms/buttons',
    'forms/fields',
    'layout/common',
    'layout/sidebar',
    'media/captions',
    'media/galleries',
    'typography/headings',
];

based on this order(the part before slash):

var needed_order = [
    'typography',
    'forms',
    'media',
    'layout',
];

The expected result:

// [
//     'typography/headings',
//     'forms/buttons',
//     'forms/fields',
//     'media/captions',
//     'media/galleries',
//     'layout/common',
//     'layout/sidebar',
// ]

Shreevardhan · Accepted Answer · 2018-07-07 11:52:35Z

5

This should help

Array.prototype.sort takes a compareFunction as an argument to decide the sort order. Read more

If compareFunction is supplied, all non-undefined array elements are sorted according to the return value of the compare function (all undefined elements are sorted to the end of the array, with no call to compareFunction)

var list = [
  'forms/buttons',
  'forms/fields',
  'layout/common',
  'layout/sidebar',
  'media/captions',
  'media/galleries',
  'typography/headings',
];

var needed_order = [
  'typography',
  'forms',
  'media',
  'layout',
];

list.sort((a, b) => needed_order.indexOf(a.split('/')[0]) - needed_order.indexOf(b.split('/')[0]));

console.log(list);

edited Jul 7, 2018 at 11:52

answered Jul 7, 2018 at 11:46

Shreevardhan

12.7k3 gold badges39 silver badges53 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Shreevardhan Over a year ago

@Luca you can learn more about the Array sort compareFunction here.

Luca Kiebel Over a year ago

I don't need to learn more about the topic, you should add Information abiut this to your Post ;-)

Andrei Surdu Over a year ago

Excellent. Thank you very much for the help. ✌

Jonas Wilms · Accepted Answer · 2018-07-07 11:46:59Z

0

You could sort by the first appearance in the ˋneeded_orderˋ array:

const getPriority = el => needed_order.findIndex(order => el.includes(order));

list.sort((a, b) => getPriority(a) - getPriority(b));

answered Jul 7, 2018 at 11:46

Jonas Wilms

139k20 gold badges164 silver badges164 bronze badges

Comments

Nina Scholz · Accepted Answer · 2018-07-07 11:55:58Z

You could sort by the infex of the string which starts with the items to sort.

var list = ['forms/buttons', 'forms/fields', 'layout/common', 'layout/sidebar', 'media/captions', 'media/galleries', 'typography/headings'],
    order = ['typography', 'forms', 'media', 'layout'];

list.sort((a, b) => order.findIndex(v => a.startsWith(v)) - order.findIndex(v => b.startsWith(v)));

console.log(list);

A faster version for huge data, could be to store the key index values in a hash table and use it for sorting.

function getS(s) { return s.match(/^[^\/]*/)[0]; }

var list = ['forms/buttons', 'forms/fields', 'layout/common', 'layout/sidebar', 'media/captions', 'media/galleries', 'typography/headings'],
    order = ['typography', 'forms', 'media', 'layout'],
    hash = Object.assign(...order.map((k, v) => ({ [k]: v })));

list.sort((a, b) => hash[getS(a)] - hash[getS(b)]);

console.log(list);

Collectives™ on Stack Overflow

Sort an array based on another array's values

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related