http-utils

src/http.ts

@@ -0,0 +1,25 @@
+export const postJson = <T>(url: string, body: T) =>
+  fetch(url, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify(body),
+  });
+
+export const fetchJson = <T>(...params: Parameters<typeof fetch>) =>
+  fetch(...params).then(async (x: Response) => {
+    if (x.status === 200) return x.json() as Promise<T>;
+    throw new Error(
+      `Failed fetching ${params[0]} ${x.status} ${x.statusText} ${await x
+        .text()}`,
+    );
+  });
+
+export const fetchText = (...x: Parameters<typeof fetch>) =>
+  fetch(...x).then(async (x: Response) => {
+    if (x.status === 200) return x.text();
+    throw new Error(
+      `failed fetching ${x.status} ${x.statusText} ${await x
+        .text()
+        .catch(() => "")}`,
+    );
+  });

src/index.ts

@@ -3,6 +3,7 @@ export * from "./composition.ts";
 export * from "./conditional.ts";
 export * from "./debug.ts";
 export * from "./filter.ts";
+export * from "./http.ts";
 export * from "./io.ts";
 export * from "./juxt.ts";
 export * from "./lock.ts";

src/mapping.ts

@@ -144,9 +144,9 @@ export const keyFilter = <Value, F extends Func>(
   // @ts-expect-error can't infer typing here
   entryFilter(pipe(head, f));
 
-export const valMap = <Key extends RecordKey, F extends Func>(
-  f: F,
-): EntryMap<F, Key, ParamOf<F>, Key, ReturnTypeUnwrapped<F>> =>
+export const valMap = <Key extends RecordKey, OldValue, NewValue>(
+  f: (old: OldValue) => NewValue | ((old: OldValue) => Promise<NewValue>),
+): EntryMap<typeof f, Key, OldValue, Key, NewValue> =>
   // @ts-expect-error can't infer typing here
   entryMap(stack(identity, f));
 

src/object.test.ts

@@ -1,12 +1,15 @@
 import { assertEquals } from "std-assert";
 import { removeKey } from "./object.ts";
 
+type t = { a?: number; b: number };
+
 Deno.test("remove key", () => {
-  type t = { a?: number; b: number };
   assertEquals(
     removeKey<t>(
       "a",
     )({ a: 1, b: 2 }),
     { b: 2 },
   );
 });
+
+const x = removeKey<t>("b")({ a: 1, b: 2 });