arguments passed to Message::react

[Bunch-of-cells]

The signature of the function is:

pub async fn react(
        &self,
        cache_http: impl CacheHttp,
        reaction_type: impl Into<ReactionType>,
    ) -> Result<Reaction>

What do you pass into the reaction_type parameter? Please explain with an example

[arqunis]

The job of ReactionType is to handle two kinds of emoji types:

• Unicode -- these are emojis that exist within the Unicode standard, which as a result, are represented as characters. When the Discord client encounters these characters, they're swapped with the emoji image they represent. To be specific, the characters are replaced with Twitter's https://twemoji.twitter.com/.
• Custom -- these are emojis unique to a guild, represented in a message in the format of <a?:id:name> (the ? means that "a" may be omitted). Custom emojis are just regular static (jpg, png) or animated (gif) images.

Message::react uses the Into trait to allow users to pass emoji data into the function without having to manually construct ReactionType. The kinds of data you may pass depends on ReactionType's From implementations, which you may find at https://serenity-rs.github.io/serenity/next/serenity/model/channel/enum.ReactionType.html#impl-From%3CEmoji%3E

As an example, here is how you would react to a message with a Unicode emoji:

let ctx: &Context = ...;
let msg: &Message = ...;

msg.react(ctx, '😄').await?;

And here's with a custom emoji (assuming 1234 is a valid emoji ID and so is foo a name, and the emoji itself isn't animated):

use serenity::model::id::EmojiId;
use serenity::model::misc::EmojiIdentifier;

let ctx: &Context = ...;
let msg: &Message = ...;

msg.react(ctx, EmojiIdentifier { animated: false, id: EmojiId(1234), name: "foo".to_string() }).await?;

Of course, this doesn't stop you from using ReactionType directly:

let ctx: &Context = ...;
let msg: &Message = ...;

msg.react(ctx, ReactionType::Unicode("🐱".to_string())).await?;