This is an example of my array :
[
1: { name: 'blablabla', difficulty: 'A2' },
2: { name: 'bla', difficulty: 'A1' },
3: { name: 'blablablabla', difficulty: 'B1' },
4: { name: 'blablablabla', difficulty: 'B2' },
5: { name: 'blablablabla', difficulty: 'A2' }
]
my_level: 'B2'
I want to sort the array so that my level of difficulty is the first item, i tried to use sort() but it's only to sort by 'ASC' or 'DESC', anyone have an idea of how to do it ? Thanks !
You could sort by checking the value of difficulty with the wanted difficulty.
This approach moves the wanted value to top of the array.
const
array = [{ name: 'blablabla', difficulty: 'A2' }, { name: 'bla', difficulty: 'A1' }, { name: 'blablablabla', difficulty: 'B1' }, { name: 'blablablabla', difficulty: 'B2' }, { name: 'blablablabla', difficulty: 'A2' }]
difficulty = 'B2';
array.sort((a, b) => (b.difficulty === difficulty) - (a.difficulty === difficulty));
console.log(array);.as-console-wrapper { max-height: 100% !important; top: 0; }There's no need to sort it:
arr = [
{ name: 'blablabla', difficulty: 'A2' },
{ name: 'bla', difficulty: 'A1' },
{ name: 'blablablabla', difficulty: 'B1' },
{ name: 'blablablabla', difficulty: 'B2' },
{ name: 'blablablabla', difficulty: 'A2' },
{ name: 'one more', difficulty: 'B2' },
]
my_level = 'B2'
newArr = [
...arr.filter(x => x.difficulty === my_level),
...arr.filter(x => x.difficulty !== my_level),
]
console.log(newArr)Advantages: 1) faster (I guess), 2) doesn't change the order, 3) doesn't break the original array
Here's some generic (and even faster) code:
// split array into two parts:
// part 0 - where predicate is false
// part 1 - where predicate is true
function partition(ary, predicate) {
let parts = [[], []];
for (let x of arr)
parts[predicate(x) ? 1 : 0].push(x);
return parts;
}
//
newArr = [].concat(...partition(arr, x => x.difficulty !== my_level))
.slice()-ing around the item index. Which would have added an undefined if the item wasn't found so, .filter() is probably the more robust approach for an immutable shifting of an item to the front.
splice it out... But I hate splices ;)Provide a compare function to sort that takes in two parameters lets say a and b, and returns a value based on the following table.
a.difficulty === desired |
b.difficulty === desired |
Value returned by compare |
|---|---|---|
| true | true | 0 |
| true | false | -1 |
| false | true | 1 |
| false | false | 0 |
const
data = [
{ name: "blablabla", difficulty: "A2" },
{ name: "bla", difficulty: "A1" },
{ name: "blablablabla", difficulty: "B1" },
{ name: "blablablabla", difficulty: "B2" },
{ name: "blablablabla", difficulty: "A2" },
],
desired = "B2",
table = { true: { true: 0, false: -1 }, false: { true: 1, false: 0 } },
sortedData = [...data].sort(
(a, b) => table[a.difficulty === desired][b.difficulty === desired]
);
console.log(sortedData);