Merge pull request Expensify#26970 from software-mansion-labs/ts-migr…

…ation/compose

[TS migration] Migrate 'compose.js' lib to TypeScript

src/libs/compose.ts

@@ -0,0 +1,71 @@
+/* eslint-disable @typescript-eslint/ban-types */
+/* eslint-disable import/export */
+
+/**
+ * This is a utility function taken directly from Redux. (We don't want to add Redux as a dependency)
+ * It enables functional composition, useful for the chaining/composition of HOCs.
+ *
+ * For example, instead of:
+ *
+ * export default hoc1(config1, hoc2(config2, hoc3(config3)))(Component);
+ *
+ * Use this instead:
+ *
+ * export default compose(
+ *     hoc1(config1),
+ *     hoc2(config2),
+ *     hoc3(config3),
+ * )(Component)
+ */
+export default function compose(): <R>(a: R) => R;
+
+export default function compose<F extends Function>(f: F): F;
+
+/* two functions */
+export default function compose<A extends unknown[], R1, R2>(f1: (...args: A) => R1, f2: (a: R1) => R2): (...args: A) => R2;
+
+/* three functions */
+export default function compose<A extends unknown[], R1, R2, R3>(f1: (...args: A) => R1, f2: (a: R1) => R2, f3: (a: R2) => R3): (...args: A) => R3;
+
+/* four functions */
+export default function compose<A extends unknown[], R1, R2, R3, R4>(f1: (...args: A) => R1, f2: (a: R1) => R2, f3: (a: R2) => R3, f4: (a: R3) => R4): (...args: A) => R4;
+
+/* five functions */
+export default function compose<A extends unknown[], R1, R2, R3, R4, R5>(
+    f1: (...args: A) => R1,
+    f2: (a: R1) => R2,
+    f3: (a: R2) => R3,
+    f4: (a: R3) => R4,
+    f5: (a: R4) => R5,
+): (...args: A) => R5;
+
+/* six functions */
+export default function compose<A extends unknown[], R1, R2, R3, R4, R5, R6>(
+    f1: (...args: A) => R1,
+    f2: (a: R1) => R2,
+    f3: (a: R2) => R3,
+    f4: (a: R3) => R4,
+    f5: (a: R4) => R5,
+    f6: (a: R5) => R6,
+): (...args: A) => R6;
+
+/* rest */
+export default function compose<R>(f1: (a: unknown) => R, ...funcs: Function[]): (...args: unknown[]) => R;
+
+export default function compose(...funcs: Function[]): Function {
+    if (funcs.length === 0) {
+        // infer the argument type so it is usable in inference down the line
+        return <T>(arg: T) => arg;
+    }
+
+    if (funcs.length === 1) {
+        return funcs[0];
+    }
+
+    return funcs.reduce(
+        (a, b) =>
+            (...args: unknown[]) =>
+                // eslint-disable-next-line @typescript-eslint/no-unsafe-return
+                a(b(...args)),
+    );
+}