Alphanumeric sorting in typescript

If you want full control over the sort order of the delimited values, you'll not be able to avoid splitting the values first. The solution below uses the compare2By() higher-order function to let you choose the sort key order and ascending/descending ordering per key.

(UPDATED to support key specific sort orders)

type Comparator<T> = (a: T, b: T) => number;

function compareAsc<T>(a: T, b: T) {
  return a < b ? -1 : a > b ? 1 : 0;
}

function compareDesc<T>(a: T, b: T) {
  return a < b ? 1 : a > b ? -1 : 0;
}

function compare2By<T extends any[]>(
    x = 0,
    y = 1,
    cmpX: Comparator<T[0]> = compareAsc,
    cmpY: Comparator<T[1]> = compareAsc
) {
  return (a: T, b: T) =>
    cmpX(a[x], b[x]) || cmpY(a[y], b[y]);
}

function sortDelimited(src: string[], sortFn: Comparator<number[]>, del = "_") {
  return src
    .map((x) => x.split(del))
    // optional int coercion, not sure if needed for OP
    .map((x) => x.map((y) => parseInt(y)))
    .sort(sortFn)
    .map((x) => x.join(del));
}

console.log(
    JSON.stringify(sortDelimited(
        ['1_11', '1_10', '1_9', '1_1', '1_0'],
        // UPDATED: use total descending order
        // for both first and second sort key
        compare2By(0, 1, compareDesc, compareDesc)
    ))
)

// ["1_11","1_10","1_9","1_1","1_0"]

Playground link

this will sort the array:

this.array = this.array.sort((a, b) => {
  return +a.replace('_', '') > +b.replace('_', '') ? -1 : a === b ? 0 : 1
})