feat(utils/compose): adds create argument to compose; improves typings

src/utils/compose.ts

@@ -1,6 +1,13 @@
+import { asNew } from '~/helpers';
+
 export default function compose(
-  ...fns: Array<(value: any) => any>
-): (value: any) => any {
+  ...fns: Array<<T>(promise: Promise<T>, create?: boolean) => Promise<T>>
+): <T>(promise: Promise<T>, create?: boolean) => Promise<T> {
+  const fn = trunk(...fns);
+  return (promise, create) => fn(asNew(promise, create));
+}
+
+export function trunk(...fns: Array<(value: any) => any>): (value: any) => any {
   if (fns.length === 0) return (arg: any) => arg;
   if (fns.length === 1) return fns[0];
 

test/utils/compose.test.ts

@@ -1,23 +1,69 @@
-import compose from '~/utils/compose';
+import compose, { trunk } from '~/utils/compose';
+import status from '~/compose/status';
+import timed from '~/compose/timed';
 
-test(`Doesn't throw on empty`, () => {
-  expect(() => compose()).not.toThrow();
-});
-test(`Returns function`, () => {
-  expect(typeof compose()).toBe('function');
-});
-test(`Works for 0 args`, () => {
-  expect(compose()(100)).toBe(100);
-});
-test(`Works for 1 arg`, () => {
-  expect(compose((x) => x * 2)(100)).toBe(200);
+describe(`compose`, () => {
+  test(`no fn`, async () => {
+    const promise = Promise.resolve(1);
+    const fn = compose();
+
+    expect(fn(promise)).toBe(promise);
+    await expect(fn(promise)).resolves.toBe(1);
+
+    expect(fn(promise, true)).not.toBe(promise);
+    await expect(fn(promise, true)).resolves.toBe(1);
+  });
+  test(`single fn`, async () => {
+    const promise = Promise.resolve(1);
+    const fn = compose(status);
+
+    expect(fn(promise)).toBe(promise);
+    expect(fn(promise)).toHaveProperty('status');
+    await expect(fn(promise)).resolves.toBe(1);
+
+    expect(fn(promise, true)).not.toBe(promise);
+    expect(fn(promise, true)).toHaveProperty('status');
+    await expect(fn(promise, true)).resolves.toBe(1);
+  });
+  test(`multiple fns`, async () => {
+    const promise = Promise.resolve(1);
+    const fn = compose(
+      status,
+      timed
+    );
+
+    expect(fn(promise)).toBe(promise);
+    expect(fn(promise)).toHaveProperty('status');
+    expect(fn(promise)).toHaveProperty('time');
+    await expect(fn(promise)).resolves.toBe(1);
+
+    expect(fn(promise, true)).not.toBe(promise);
+    expect(fn(promise, true)).toHaveProperty('status');
+    expect(fn(promise)).toHaveProperty('time');
+    await expect(fn(promise, true)).resolves.toBe(1);
+  });
 });
-test(`Executes in order`, () => {
-  const fns = [
-    (x: number) => x / 2,
-    (x: number) => x / 5,
-    (x: number) => x * 6,
-    (x: number) => x / 3
-  ];
-  expect(compose(...fns)(100)).toBe(20);
+
+describe(`trunk`, () => {
+  test(`Doesn't throw on empty`, () => {
+    expect(() => trunk()).not.toThrow();
+  });
+  test(`Returns function`, () => {
+    expect(typeof trunk()).toBe('function');
+  });
+  test(`Works for 0 args`, () => {
+    expect(trunk()(100)).toBe(100);
+  });
+  test(`Works for 1 arg`, () => {
+    expect(trunk((x) => x * 2)(100)).toBe(200);
+  });
+  test(`Executes in order`, () => {
+    const fns = [
+      (x: number) => x / 2,
+      (x: number) => x / 5,
+      (x: number) => x * 6,
+      (x: number) => x / 3
+    ];
+    expect(trunk(...fns)(100)).toBe(20);
+  });
 });