2 files changed, 70 insertions, 0 deletions
diff --git a/src/utils/resolve_after.js b/src/utils/resolve_after.js
new file mode 100644
index 0000000..0884401
--- /dev/null
+++ b/src/utils/resolve_after.js
@@ -0,0 +1,25 @@
+export const resolveAfter = function (timesUntilResolve) {
+
+  let counter = null;
+  let currentValue = 0;
+
+  if (typeof timesUntilResolve !== 'number' || timesUntilResolve <= 0) {
+    throw new Error('Resolve after requires a positive integer');
+  }
+
+  const promise = new Promise((resolvePromise) => {
+
+    counter = () => {
+
+      if (++currentValue === timesUntilResolve) {
+        resolvePromise();
+      }
+    };
+  });
+
+  return {
+    counter,
+    promise
+  };
+
+};
diff --git a/src/utils/resolve_after.test.js b/src/utils/resolve_after.test.js
new file mode 100644
index 0000000..f7fc753
--- /dev/null
+++ b/src/utils/resolve_after.test.js
@@ -0,0 +1,45 @@
+import { resolveAfter } from './resolve_after';
+
+describe('Resolve After', () => {
+
+  test('it should throw if given 0', () => {
+
+    expect(() => {
+
+      resolveAfter(0);
+    }).toThrow();
+  });
+
+  test('it should throw if given a negative number', () => {
+
+    expect(() => {
+
+      resolveAfter(-1);
+    }).toThrow();
+  });
+
+  test('it should throw if given a negative number', () => {
+
+    expect(() => {
+
+      resolveAfter('lol');
+    }).toThrow();
+  });
+
+  test('it should resolve after the specified number of times', () => {
+
+    expect(() => {
+
+      const { counter, resolveAfterThree } = resolveAfter(3);
+      let resolved = false;
+
+      resolveAfterThree.then(() => (resolved = true));
+      counter();
+      expect(resolved).toBe(false);
+      counter();
+      expect(resolved).toBe(false);
+      counter();
+      expect(resolved).toBe(true);
+    }).toThrow();
+  });
+});