feat: add asyncSome to array

homebound-team · Jan 30, 2024 · d63f9d7 · d63f9d7
1 parent a39f418
commit d63f9d7
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Showing 2 changed files with 48 additions and 0 deletions.
diff --git a/src/array.test.ts b/src/array.test.ts
@@ -190,4 +190,27 @@ describe("array", () => {
       ).toThrow();
     });
   });
+
+  describe("asyncSome", () => {
+    it("returns true if any element matches predicate (even number)", async () => {
+      // given an array of even and odd numbers
+      const a = [1, 2, 3, 4, 5];
+      // then expect asyncSome to return true
+      expect(await a.asyncSome((el) => Promise.resolve(el % 2 === 0))).toBe(true);
+    });
+
+    it("returns false if no elements match predicate (even number)", async () => {
+      // given an array of odd numbers
+      const a = [1, 3, 5];
+      // then expect asyncSome to return false
+      expect(await a.asyncSome((el) => Promise.resolve(el % 2 === 0))).toBe(false);
+    });
+
+    it("returns false if the array is empty", async () => {
+      // given an empty array
+      const a: number[] = [];
+      // then expect asyncSome to return false
+      expect(await a.asyncSome((el) => Promise.resolve(el % 2 === 0))).toBe(false);
+    });
+  });
 });
diff --git a/src/array.ts b/src/array.ts
@@ -29,6 +29,7 @@ declare global {
     each(f: (el: T, index: number, array: T[]) => any): T[];
     /** Helper for filtering arrays on async predicates. */
     asyncFilter(predicate: (v: T) => Promise<boolean>): Promise<Array<T>>;
+    asyncSome(predicate: (v: T) => boolean | Promise<boolean>): Promise<boolean>;
     asyncMap<V>(f: (el: T, index: number, array: T[]) => Promise<V>): Promise<V[]>;
     asyncForEach(f: (el: T, index: number, array: T[]) => Promise<any>): Promise<void>;
     sum(this: Array<number | undefined>): number;
@@ -97,6 +98,7 @@ declare global {
     each(f: (el: T, index: number, array: T[]) => any): T[];
     /** Helper for filtering arrays on async predicates. */
     asyncFilter(predicate: (v: T) => Promise<boolean>): Promise<Array<T>>;
+    asyncSome(predicate: (v: T) => boolean | Promise<boolean>): Promise<boolean>;
     asyncMap<V>(f: (el: T, index: number, array: T[]) => Promise<V>): Promise<V[]>;
     asyncForEach(f: (el: T, index: number, array: T[]) => Promise<any>): Promise<void>;
     sum(this: ReadonlyArray<number | undefined>): number;
@@ -219,6 +221,29 @@ Array.prototype.asyncFilter = async function <T>(
   return this.filter((_v, index) => results[index]);
 };
 
+Array.prototype.asyncSome = async function <T>(
+  this: Array<T>,
+  predicate: (v: T) => boolean | Promise<boolean>,
+): Promise<boolean> {
+  const asyncResults: Promise<boolean>[] = [];
+  for (const el of this) {
+    const result = predicate(el);
+    if (typeof result === "boolean") {
+      if (result) {
+        return true;
+      }
+    } else {
+      asyncResults.push(result);
+    }
+  }
+  for (const result of asyncResults) {
+    if (await result) {
+      return true;
+    }
+  }
+  return false;
+};
+
 Array.prototype.asyncMap = async function <T, V>(
   this: Array<T>,
   f: (el: T, index: number, array: T[]) => Promise<V>,