feat(sortby): add sortBy function

Author: djcsdy

index.test.ts

@@ -49,6 +49,7 @@ import {
     scanRight1,
     slice,
     sort,
+    sortBy,
     split,
     sum,
     tail,
@@ -514,6 +515,30 @@ test("sort", t => {
     );
 });
 
+test("sortBy", t => {
+    t.deepEqual(
+        sortBy(
+            [
+                {x: "a", y: 2},
+                {x: "b", y: 4},
+                {x: "c", y: 3},
+                {x: "d", y: 1}
+            ],
+            ({y}) => y
+        ),
+        [
+            {x: "d", y: 1},
+            {x: "a", y: 2},
+            {x: "c", y: 3},
+            {x: "b", y: 4}
+        ]
+    );
+    t.deepEqual(
+        sortBy([-2, 4, -3, 1], e => Math.abs(e)),
+        [1, -2, -3, 4]
+    );
+});
+
 test("forEach", t => {
     const a = ["a", "b", "c"];
     let s = "";

index.ts

@@ -1524,6 +1524,19 @@ export function sortFn<T>(comparator: Comparator<T>): (array: ArrayLike<T>) => T
     return array => sort(array, comparator);
 }
 
+export function sortBy<T>(array: ArrayLike<T>, select: SortSelect<T>): T[] {
+    return sort(array, (a, b) => defaultCompare(select(a) as any, select(b) as any));
+}
+
+export type SortSelect<T> =
+    | ((element: T) => boolean)
+    | ((element: T) => number)
+    | ((element: T) => string);
+
+export function sortByFn<T>(select: SortSelect<T>): (array: ArrayLike<T>) => T[] {
+    return array => sortBy(array, select);
+}
+
 export function forEach<T>(
     array: ArrayLike<T>,
     f: (element: T, index: number) => void