Sort an array by multiple keys
Sort objects by one field, then break ties with another, with ascending or descending order per field.
- JavaScript
- GreenSnippets
- MIT
- Executed with Node.js 22
function sortBy(array, ...rules) {
// rule: [keyOrFn, "asc" | "desc"]
const compare = (a, b) => {
for (const [by, dir = "asc"] of rules) {
const get = typeof by === "function" ? by : (item) => item[by];
const x = get(a);
const y = get(b);
let result = 0;
if (typeof x === "string" && typeof y === "string") result = x.localeCompare(y);
else if (x < y) result = -1;
else if (x > y) result = 1;
if (result !== 0) return dir === "desc" ? -result : result;
}
return 0;
};
return [...array].sort(compare);
}Example / expected output
sortBy(people, ["lastName"], ["age", "desc"])How it works
Array.prototype.sort is stable and the comparator below returns the first non-zero result across the rules. Strings are compared with localeCompare so accents and case behave naturally. The input array is copied, not mutated.
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