Return cached response immediately if not stale

index.js

@@ -18,6 +18,7 @@ const isRetryAllowed = require('is-retry-allowed');
 const Buffer = require('safe-buffer').Buffer;
 const expired = require('expired');
 const normalizeUrl = require('normalize-url');
+const Response = require('http-response-object');
 const pkg = require('./package');
 
 function requestAsEventEmitter(opts) {
@@ -99,7 +100,22 @@ function requestAsEventEmitter(opts) {
 		});
 	};
 
-	get(opts);
+	if (opts.cache && opts.method === 'GET') {
+		const key = normalizeUrl(requestUrl);
+		opts.cache.get(key, (err, value) => {
+			if (err) {
+				return get(opts);
+			}
+			const cachedResponse = JSON.parse(value);
+			if (expired(cachedResponse.headers) === false) {
+				const response = responseFromCache(requestUrl, cachedResponse);
+				ee.emit('response', response);
+			}
+		});
+	} else {
+		get(opts);
+	}
+
 	return ee;
 }
 
@@ -315,6 +331,10 @@ function normalizeArguments(url, opts) {
 	return opts;
 }
 
+function responseFromCache(url, cachedResponse) {
+	return new Response(200, cachedResponse.headers, Buffer.from(cachedResponse.body), url);
+}
+
 function got(url, opts) {
 	try {
 		return asPromise(normalizeArguments(url, opts));

package.json

@@ -46,6 +46,7 @@
     "duplexer3": "^0.1.4",
     "expired": "^1.3.8",
     "get-stream": "^3.0.0",
+    "http-response-object": "^1.1.0",
     "is-redirect": "^1.0.0",
     "is-retry-allowed": "^1.0.0",
     "is-stream": "^1.0.0",