Updated connect method docs (#1990)

* docs: updated connect method jsdoc and readme

* docs: updated lazyConnect jsdoc and updated the readme

* docs: adjusted the lazyConnect jsdoc

* docs: typo fix

Author: PavelPashov

README.md

@@ -826,7 +826,7 @@ The Redis instance will emit some events about the state of the connection to th
 | :----------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | connect      | emits when a connection is established to the Redis server.                                                                                                                                                                                     |
 | ready        | If `enableReadyCheck` is `true`, client will emit `ready` when the server reports that it is ready to receive commands (e.g. finish loading data from disk).<br>Otherwise, `ready` will be emitted immediately right after the `connect` event. |
-| error        | emits when an error occurs while connecting.<br>However, ioredis emits all `error` events silently (only emits when there's at least one listener) so that your application won't crash if you're not listening to the `error` event.           |
+| error        | emits when an error occurs while connecting.<br>When `lazyConnect` is false, ioredis emits all `error` events silently (only emits when there's at least one listener) so that your application won't crash if you're not listening to the `error` event.<br> However when `lazyConnect` is true and `redis.connect()` is explicitly called it will return a promise which might reject with an error. If `redis.connect()` is not called explicitly, ioredis will try to connect automatically on the first command and emit the `error` event silently.                                                      |
 | close        | emits when an established Redis server connection has closed.                                                                                                                                                                                   |
 | reconnecting | emits after `close` when a reconnection will be made. The argument of the event is the time (in ms) before reconnecting.                                                                                                                        |
 | end          | emits after `close` when no more reconnections will be made, or the connection is failed to establish.                                                                                                                                          |

lib/Redis.ts

@@ -170,7 +170,8 @@ class Redis extends Commander implements DataHandledable {
    * unless `lazyConnect: true` is passed.
    *
    * When calling this method manually, a Promise is returned, which will
-   * be resolved when the connection status is ready.
+   * be resolved when the connection status is ready. The promise can reject
+   * if the connection fails, times out, or if Redis is already connecting/connected.
    */
   connect(callback?: Callback<void>): Promise<void> {
     const promise = new Promise<void>((resolve, reject) => {

lib/redis/RedisOptions.ts

@@ -174,7 +174,8 @@ export interface CommonRedisOptions extends CommanderOptions {
   /**
    * When a Redis instance is initialized, a connection to the server is immediately established. Set this to
    * true will delay the connection to the server until the first command is sent or `redis.connect()` is called
-   * explicitly.
+   * explicitly. When `redis.connect()` is called explicitly, a Promise is returned, which will be resolved
+   * when the connection is ready or rejected when it fails. The rejection should be handled by the user.
    *
    * @default false
    */