V5 bringing RESP3, Sentinel and TypeMapping to node-redis

RESP3 Support
   - Some commands responses in RESP3 aren't stable yet and therefore return an "untyped" ReplyUnion.
 
Sentinel

TypeMapping

Correctly types Multi commands

Note: some API changes to be further documented in v4-to-v5.md

packages/client/lib/RESP/encoder.ts

@@ -0,0 +1,28 @@
+import { RedisArgument } from './types';
+
+const CRLF = '\r\n';
+
+export default function encodeCommand(args: Array<RedisArgument>): Array<RedisArgument> {
+  const toWrite: Array<RedisArgument> = [];
+
+  let strings = '*' + args.length + CRLF;
+
+  for (let i = 0; i < args.length; i++) {
+    const arg = args[i];
+    if (typeof arg === 'string') {
+      strings += '$' + Buffer.byteLength(arg) + CRLF + arg + CRLF;
+    } else if (arg instanceof Buffer) {
+      toWrite.push(
+        strings + '$' + arg.length.toString() + CRLF,
+        arg
+      );
+      strings = CRLF;
+    } else {
+      throw new TypeError(`"arguments[${i}]" must be of type "string | Buffer", got ${typeof arg} instead.`);
+    }
+  }
+
+  toWrite.push(strings);
+
+  return toWrite;
+}