t_wの輪郭

class Token_store {
    constructor() {
        this.store = localforage.createInstance({ name: 'Tokens' });
        this.token_array = [];
        this.id_by_token = new Map();
    }
    token_get_by_id(id) {
        return this.token_array[id];
    }
    id_get_by_token(token) {
        let id = this.id_by_token.get(token);
        if (id?.constructor != Number) {
            this.add_token(token);
            id = this.id_by_token.get(token);
        }
        console.assert(id?.constructor == Number);
        return id;
    }
    add_token(token) {
        const id = this.token_array.length;
        this.token_array[id] = token;
        this.id_by_token.set(token, id);
        this.save_async_with_delay();
    }
    async load_async() {
        this.token_array = await this.store.getItem('token_array');
        for (let i = 0; i < this.token_array.length; i++) {
            this.id_by_token.set(token, i);
        }
    }
    async save_async() {
        this.store.setItem('token_array', this.token_array);
    }
    async save_async_with_delay() {
        if (this.saving) {
            return;
        }
        await this.save_async();
        setTimeout(() => {
            this.saving = false;
        }, SAVE_DELAY);
    }
}