Retry on network errors in Firefox and Safari too (#42)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

index.d.ts

@@ -52,8 +52,8 @@ declare const pRetry: {
 	/**
 	Returns a `Promise` that is fulfilled when calling `input` returns a fulfilled promise. If calling `input` returns a rejected promise, `input` is called again until the max retries are reached, it then rejects with the last rejection reason.
 
-	It doesn't retry on `TypeError` as that's a user error. The only exclusion to this logic is when `TypeError` is thrown by `fetch`'s API with the message 'Failed to fetch', [which indicates that a request was not successful due to a network error](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Checking_that_the_fetch_was_successful). 
-	However, beware that `fetch` may throw `TypeError` with different error messages on different platforms for similar situations. See [whatwg/fetch#526 (comment)](https://github.com/whatwg/fetch/issues/526#issuecomment-554604080)."  
+	Does not retry on most `TypeErrors`, with the exception of network errors. This is done on a best case basis as different browsers have different [messages](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Checking_that_the_fetch_was_successful) to indicate this. 
+	See [whatwg/fetch#526 (comment)](https://github.com/whatwg/fetch/issues/526#issuecomment-554604080)
 
 	@param input - Receives the number of attempts as the first argument and is expected to return a `Promise` or any value.
 	@param options - Options are passed to the [`retry`](https://github.com/tim-kos/node-retry#retryoperationoptions) module.

index.js

@@ -1,6 +1,12 @@
 'use strict';
 const retry = require('retry');
 
+const networkErrorMsgs = [
+	'Failed to fetch', // Chrome
+	'NetworkError when attempting to fetch resource', // Firefox
+	'The Internet connection appears to be offline' // Safari
+];
+
 class AbortError extends Error {
 	constructor(message) {
 		super();
@@ -27,6 +33,8 @@ const decorateErrorWithCounts = (error, attemptNumber, options) => {
 	return error;
 };
 
+const isNetworkError = errorMessage => networkErrorMsgs.includes(errorMessage);
+
 const pRetry = (input, options) => new Promise((resolve, reject) => {
 	options = {
 		onFailedAttempt: () => {},
@@ -48,7 +56,7 @@ const pRetry = (input, options) => new Promise((resolve, reject) => {
 			if (error instanceof AbortError) {
 				operation.stop();
 				reject(error.originalError);
-			} else if (error instanceof TypeError && error.message !== 'Failed to fetch') {
+			} else if (error instanceof TypeError && !isNetworkError(error.message)) {
 				operation.stop();
 				reject(error);
 			} else {

readme.md

@@ -39,7 +39,8 @@ const run = async () => {
 Returns a `Promise` that is fulfilled when calling `input` returns a fulfilled promise. If calling `input` returns a rejected promise, `input` is called again until the maximum number of retries is reached. It then rejects with the last rejection reason.
 
 
-It doesn't retry on `TypeError` as that's a user error. The only exclusion to this logic is when `TypeError` is thrown by `fetch`'s API with the message 'Failed to fetch', [which indicates that a request was not successful due to a network error](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Checking_that_the_fetch_was_successful). However, beware that `fetch` may throw `TypeError` with different error messages on different platforms for similar situations. See [whatwg/fetch#526 (comment)](https://github.com/whatwg/fetch/issues/526#issuecomment-554604080)."  
+Does not retry on most `TypeErrors`, with the exception of network errors. This is done on a best case basis as different browsers have different [messages](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Checking_that_the_fetch_was_successful) to indicate this. See [whatwg/fetch#526 (comment)](https://github.com/whatwg/fetch/issues/526#issuecomment-554604080)
+
 
 #### input