docs: Add examples and mention Retry-After in README

README.md

@@ -26,17 +26,25 @@ axios.get('http://example.com/test') // The first request fails and the second r
  result.data; // 'ok'
  });
 
+// No retry delay
+axiosRetry(axios, { retryDelay: axiosRetry.noDelay });
+
 // Exponential back-off retry delay between requests
 axiosRetry(axios, { retryDelay: axiosRetry.exponentialDelay });
 
-// Liner retry delay between requests
+// Liner retry delay between requests; note the different function signature
 axiosRetry(axios, { retryDelay: axiosRetry.linearDelay() });
 
 // Custom retry delay
 axiosRetry(axios, { retryDelay: (retryCount) => {
  return retryCount * 1000;
 }});
 
+// Exponential back-off retry delay with a custom initial delay
+axiosRetry(axios, { retryDelay: (retryCount, error) => {
+ return axiosRetry.exponentialDelay(retryCount, error, 1000);
+}});
+
 // Works with custom axios instances
 const client = axios.create({ baseURL: 'http://example.com' });
 axiosRetry(client, { retries: 3 });
@@ -62,15 +70,19 @@ client
 
 ## Options
 
-| Name | Type | Default | Description |
-| --- | --- | --- | --- |
-| retries | `Number` | `3` | The number of times to retry before failing. 1 = One retry after first failure |
-| retryCondition | `Function` | `isNetworkOrIdempotentRequestError` | A callback to further control if a request should be retried. By default, it retries if it is a network error or a 5xx error on an idempotent request (GET, HEAD, OPTIONS, PUT or DELETE). |
-| shouldResetTimeout | `Boolean` | false | Defines if the timeout should be reset between retries |
-| retryDelay | `Function` | `function noDelay() { return 0; }` | A callback to further control the delay in milliseconds between retried requests. By default there is no delay between retries. Another option is exponentialDelay ([Exponential Backoff](https://developers.google.com/analytics/devguides/reporting/core/v3/errors#backoff)) or `linearDelay`. The function is passed `retryCount` and `error`. |
-| onRetry | `Function` | `function onRetry(retryCount, error, requestConfig) { return; }` | A callback to notify when a retry is about to occur. Useful for tracing and you can any async process for example refresh a token on 401. By default nothing will occur. The function is passed `retryCount`, `error`, and `requestConfig`. |
-| onMaxRetryTimesExceeded | `Function` | `function onMaxRetryTimesExceeded(error, retryCount) { return; }` | After all the retries are failed, this callback will be called with the last error before throwing the error. |
-| validateResponse | `Function \| null` | `null` | A callback to define whether a response should be resolved or rejected. If null is passed, it will fallback to the axios default (only 2xx status codes are resolved). |
+| Name | Type | Default | Description |
+| ----------------------- | ------------------ | ----------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| retries | `Number` | `3` | The number of times to retry before failing. 1 = One retry after first failure |
+| retryCondition | `Function` | `isNetworkOrIdempotentRequestError` | A callback to further control if a request should be retried. By default, it retries if it is a network error or a 5xx error on an idempotent request (GET, HEAD, OPTIONS, PUT or DELETE). |
+| shouldResetTimeout | `Boolean` | false | Defines if the timeout should be reset between retries |
+| retryDelay | `Function` | `function noDelay() { return 0; }` | A callback to further control the delay in milliseconds between retried requests. By default there is no delay between retries. Another option is exponentialDelay ([Exponential Backoff](https://developers.google.com/analytics/devguides/reporting/core/v3/errors#backoff)) or `linearDelay`. The function is passed `retryCount` and `error`. |
+| onRetry | `Function` | `function onRetry(retryCount, error, requestConfig) { return; }` | A callback to notify when a retry is about to occur. Useful for tracing and you can any async process for example refresh a token on 401. By default nothing will occur. The function is passed `retryCount`, `error`, and `requestConfig`. |
+| onMaxRetryTimesExceeded | `Function` | `function onMaxRetryTimesExceeded(error, retryCount) { return; }` | After all the retries are failed, this callback will be called with the last error before throwing the error. |
+| validateResponse | `Function \| null` | `null` | A callback to define whether a response should be resolved or rejected. If null is passed, it will fallback to the axios default (only 2xx status codes are resolved). |
+
+## Retry-After Header
+
+Note that axios-retry respects the [`Retry-After` response header](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After). If a response contains a `Retry-After` header, axios-retry will wait as long as the biggest value between the `Retry-After` header and the configured `retryDelay` option.
 
 ## Testing