1 files changed, 60 insertions, 0 deletions
diff --git a/node_modules/exponential-backoff/src/backoff.ts b/node_modules/exponential-backoff/src/backoff.ts
new file mode 100644
index 0000000..549770b
--- /dev/null
+++ b/node_modules/exponential-backoff/src/backoff.ts
@@ -0,0 +1,60 @@
+import {
+  IBackOffOptions,
+  getSanitizedOptions,
+  BackoffOptions
+} from "./options";
+import { DelayFactory } from "./delay/delay.factory";
+
+export { BackoffOptions, IBackOffOptions };
+
+/**
+ * Executes a function with exponential backoff.
+ * @param request the function to be executed
+ * @param options options to customize the backoff behavior
+ * @returns Promise that resolves to the result of the `request` function
+ */
+export async function backOff<T>(
+  request: () => Promise<T>,
+  options: BackoffOptions = {}
+): Promise<T> {
+  const sanitizedOptions = getSanitizedOptions(options);
+  const backOff = new BackOff(request, sanitizedOptions);
+
+  return await backOff.execute();
+}
+
+class BackOff<T> {
+  private attemptNumber = 0;
+
+  constructor(
+    private request: () => Promise<T>,
+    private options: IBackOffOptions
+  ) {}
+
+  public async execute(): Promise<T> {
+    while (!this.attemptLimitReached) {
+      try {
+        await this.applyDelay();
+        return await this.request();
+      } catch (e) {
+        this.attemptNumber++;
+        const shouldRetry = await this.options.retry(e, this.attemptNumber);
+
+        if (!shouldRetry || this.attemptLimitReached) {
+          throw e;
+        }
+      }
+    }
+
+    throw new Error("Something went wrong.");
+  }
+
+  private get attemptLimitReached() {
+    return this.attemptNumber >= this.options.numOfAttempts;
+  }
+
+  private async applyDelay() {
+    const delay = DelayFactory(this.options, this.attemptNumber);
+    await delay.apply();
+  }
+}