Drew Drew - 3 months ago 8
Javascript Question

Sorting Javascript array of objects by specific string order?

I have the following data:

enter image description here

and I was wondering how I could sort these in a specific order.

The order needs to be: Yellow, Blue, White, Green, Red and then within those colors, it would show the smallest number first.

So in this case, the correct sorting should be:
y2, y3, b0, b2, b6, w2, g7, r4

Does anyone have any ideas on how to accomplish that? I'm using underscore.js if that makes it easier.

Answer

This naively assumes that all elements have a valid color (or at least it sorts elements with an invalid color first):

arr.sort( ( a, b ) => {
    const colorOrder = ['yellow', 'blue', 'white', 'green', 'red'];

    const aColorIndex = colorOrder.indexOf( a.color );
    const bColorIndex = colorOrder.indexOf( b.color );

    if ( aColorIndex === bColorIndex )
        return a.card - b.card;

    return aColorIndex - bColorIndex;
} );

Example:

const sorted = [
    { color: 'yellow', card: '3' },
    { color: 'red',    card: '4' },
    { color: 'blue',   card: '6' },
    { color: 'white',  card: '2' },
    { color: 'blue',   card: '2' },
    { color: 'yellow', card: '2' },
    { color: 'blue',   card: '0' },
    { color: 'green',  card: '7' },
].sort( ( a, b ) => {
    const colorOrder = ['yellow', 'blue', 'white', 'green', 'red'];

    const aColorIndex = colorOrder.indexOf( a.color );
    const bColorIndex = colorOrder.indexOf( b.color );

    if ( aColorIndex === bColorIndex )
        return a.card - b.card;

    return aColorIndex - bColorIndex;
} );

// Result:
[
  { "color": "yellow", "card": "2" },
  { "color": "yellow", "card": "3" },
  { "color": "blue",   "card": "0" },
  { "color": "blue",   "card": "2" },
  { "color": "blue",   "card": "6" },
  { "color": "white",  "card": "2" },
  { "color": "green",  "card": "7" },
  { "color": "red",    "card": "4" }
]
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