export interface MlsReaction {
    src: string;
    amount: number;
    users: string[];
}
/** Adding twice or removing what isn't there changes nothing, so replays and reorders are safe. */
export declare function applyMlsReaction(reactions: readonly MlsReaction[] | null | undefined, change: {
    emoji: string;
    userId: string;
    action: "add" | "remove";
}): MlsReaction[];
/** What a tap on a reaction chip means for this person: take theirs off, or put it on. */
export declare function mlsReactionAction(reactions: readonly MlsReaction[] | null | undefined, emoji: string, userId: string): "add" | "remove";