stick-figure-mmo/static/playerstatemachine.js

export class StateMachine {
    constructor(owner) {
        this.owner = owner;
        this.state = null;
    }

    get() {
        return this.state;
    }

    set(next) {
        if (next === this.state) return;

        const prev = this.state;

        if (prev && typeof prev.exit === 'function') {
            prev.exit(this.owner, next);
        }

        this.state = next || null;

        if (this.state && typeof this.state.enter === 'function') {
            this.state.enter(this.owner, prev);
        }
    }
    update(dt) {
        if (this.state && typeof this.state.update === 'function') {
            this.state?.update?.(this.owner, dt);
        }
    }
}