Update redis client example with async/await syntax

Author: oleiade

src/data/markdown/docs/02 javascript api/07 k6-experimental/02 redis/10 Client.md

@@ -53,51 +53,43 @@ const redisClient = new redis.Client({
 // in the context of the measureUsingRedisData function.
 const crocodileIDs = new Array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
 
-export function measureRedisPerformance() {
+export async function measureRedisPerformance() {
   // VUs are executed in a parallel fashion,
   // thus, to ensure that parallel VUs are not
   // modifying the same key at the same time,
   // we use keys indexed by the VU id.
   const key = `foo-${exec.vu.idInTest}`;
 
-  redisClient
-    .set(`foo-${exec.vu.idInTest}`, 1)
-    .then(() => redisClient.get(`foo-${exec.vu.idInTest}`))
-    .then((value) => redisClient.incrBy(`foo-${exec.vu.idInTest}`, value))
-    .then((_) => redisClient.del(`foo-${exec.vu.idInTest}`))
-    .then((_) => redisClient.exists(`foo-${exec.vu.idInTest}`))
-    .then((exists) => {
-      if (exists !== 0) {
-        throw new Error('foo should have been deleted');
-      }
-    });
+  await redisClient.set(key, 1);
+  await redisClient.incrBy(key, 10);
+  if (await redisClient.get(key) !== '11') {
+    throw new Error('foo should have been incremented to 11');
+  }
+
+  await redisClient.del(key);
+  if (await redisClient.exists(key) !== 0) {
+    throw new Error('foo should have been deleted');
+  }
 }
 
-export function setup() {
-  redisClient.sadd('crocodile_ids', ...crocodileIDs);
+export async function setup() {
+    await redisClient.sadd('crocodile_ids', ...crocodileIDs);
 }
 
-export function measureUsingRedisData() {
+export async function measureUsingRedisData() {
   // Pick a random crocodile id from the dedicated redis set,
   // we have filled in setup().
-  redisClient
-    .srandmember('crocodile_ids')
-    .then((randomID) => {
-      const url = `https://test-api.k6.io/public/crocodiles/${randomID}`;
-      const res = http.get(url);
-
-      check(res, {
-        'status is 200': (r) => r.status === 200,
-        'content-type is application/json': (r) => r.headers['content-type'] === 'application/json',
-      });
-
-      return url;
-    })
-    .then((url) => redisClient.hincrby('k6_crocodile_fetched', url, 1));
+  const randomID = await redisClient.srandmember('crocodile_ids');
+  const url = `https://test-api.k6.io/public/crocodiles/${randomID}`;
+  const res = http.get(url);
+
+  check(res, {'status is 200': (r) => r.status === 200});
+
+  await redisClient.hincrby('k6_crocodile_fetched', url, 1);
 }
 
-export function teardown() {
-  redisClient.del('crocodile_ids');
+export async function teardown() {
+    await redisClient.del('crocodile_ids');
 }
 
 export function handleSummary(data) {