1 files changed, 85 insertions, 0 deletions
diff --git a/comm/chat/protocols/matrix/lib/p-retry/index.js b/comm/chat/protocols/matrix/lib/p-retry/index.js
new file mode 100644
index 0000000000..3679399db8
--- /dev/null
+++ b/comm/chat/protocols/matrix/lib/p-retry/index.js
@@ -0,0 +1,85 @@
+'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
+	'Network request failed' // `cross-fetch`
+];
+
+class AbortError extends Error {
+	constructor(message) {
+		super();
+
+		if (message instanceof Error) {
+			this.originalError = message;
+			({message} = message);
+		} else {
+			this.originalError = new Error(message);
+			this.originalError.stack = this.stack;
+		}
+
+		this.name = 'AbortError';
+		this.message = message;
+	}
+}
+
+const decorateErrorWithCounts = (error, attemptNumber, options) => {
+	// Minus 1 from attemptNumber because the first attempt does not count as a retry
+	const retriesLeft = options.retries - (attemptNumber - 1);
+
+	error.attemptNumber = attemptNumber;
+	error.retriesLeft = retriesLeft;
+	return error;
+};
+
+const isNetworkError = errorMessage => networkErrorMsgs.includes(errorMessage);
+
+const pRetry = (input, options) => new Promise((resolve, reject) => {
+	options = {
+		onFailedAttempt: () => {},
+		retries: 10,
+		...options
+	};
+
+	const operation = retry.operation(options);
+
+	operation.attempt(async attemptNumber => {
+		try {
+			resolve(await input(attemptNumber));
+		} catch (error) {
+			if (!(error instanceof Error)) {
+				reject(new TypeError(`Non-error was thrown: "${error}". You should only throw errors.`));
+				return;
+			}
+
+			if (error instanceof AbortError) {
+				operation.stop();
+				reject(error.originalError);
+			} else if (error instanceof TypeError && !isNetworkError(error.message)) {
+				operation.stop();
+				reject(error);
+			} else {
+				decorateErrorWithCounts(error, attemptNumber, options);
+
+				try {
+					await options.onFailedAttempt(error);
+				} catch (error) {
+					reject(error);
+					return;
+				}
+
+				if (!operation.retry(error)) {
+					reject(operation.mainError());
+				}
+			}
+		}
+	});
+});
+
+module.exports = pRetry;
+// TODO: remove this in the next major version
+module.exports.default = pRetry;
+
+module.exports.AbortError = AbortError;