Another RPG Engine stat mod problem

window.Stat = class Stat {
// Designed by Akjosch

	constructor (base) {
        this._base = base;
        this._mods = {};
        this._current = undefined;
	}

    clearCache () {
		this._current = undefined;
    }

    addMod (id, mod, equipment) {
        console.log("addMod called");
		id = String(id);
		if (!this._mods[id]) {
			this._mods[id] = [];
		}
		if(Number.isFinite(mod)) {
			mod = { add: mod };
			if (equipment === true) {
				mod.equipment = true;
			}
		}
		if(typeof mod === "object") {
			this._mods[id].push(mod);
			this.clearCache();
			return this._mods[id].indexOf(mod);
		}
    }

    removeMod (id, index) {
        console.log("removeMod called");
		if (Number.isFinite(index)) {
			console.log("index detected");
			this._mods[String(id)].deleteAt(index);
		} else {
			delete this._mods[String(id)];
		}
        this.clearCache();
    }

    clearMods () {
        this._mods = {};
        this.clearCache();
    }

	get base () {
        return this._base;
    }

	set base (newBase) {
        newBase = Number(newBase);
        /* alternative: newBase = setup.roll(newBase) for "3d6" as inputs */
        if(!Number.isFinite(newBase)) {
            newBase = 0;
        }
        if (this._base !== newBase) {
            this._base = newBase;
            this.clearCache();
        }
    }

	get current () {
        if (this._current === undefined) {
            /* gather multipliers */
            var mult = Object.values(this._mods)
				.reduce(function(bigSum, entry) { return bigSum + entry
					.map(function(m) { return Number.isFinite(m.mult) ? m.mult : 0; })
					.reduce(function(sum, add) { return sum + add; }, 0);
				}, 0);
            /* gather sums */
			var add = Object.values(this._mods)
				.reduce(function(bigSum, entry) { return bigSum + entry
					.map(function(m) { return Number.isFinite(m.add) ? m.add : 0; })
					.reduce(function(sum, add) { return sum + add; }, 0);
				}, 0);
            this._current = this.base * (mult + 1) + add;
        }
            return this._current;
    }

	get bonus () {
		return this.current - this.base;
	}

	get equipBonus () {
		var mult = Object.values(this._mods)
			.reduce(function(bigSum, entry) { return bigSum + entry
				.map(function(m) { return m.equipment === true ? m : {}; })
				.map(function(m) { return Number.isFinite(m.mult) ? m.mult : 0; })
				.reduce(function(sum, add) { return sum + add; }, 0);
			}, 0);
        var add = Object.values(this._mods)
			.reduce(function(bigSum, entry) { return bigSum + entry
				.map(function(m) { return m.equipment === true ? m : {}; })
				.map(function(m) { return Number.isFinite(m.add) ? m.add : 0; })
				.reduce(function(sum, add) { return sum + add; }, 0);
			}, 0);
		return this.base * (mult + 1) + add - this.base;
	}

	toString () {
        var mult = Object.values(this._mods)
			.map(function(m) { return Number.isFinite(m.mult) ? m.mult : 0; })
            .reduce(function(sum, add) { return sum + add; }, 0);
        var add = Object.values(this._mods)
            .map(function(m) { return Number.isFinite(m.add) ? m.add : 0; })
            .reduce(function(sum, add) { return sum + add; }, 0);
        return this.current.toFixed(2)
            + " [" + this.base.toFixed(2)
            + " x " + (mult + 1).toFixed(2)
            + (add >= 0 ? " + " + add.toFixed(2) : " - " + (-add).toFixed(2))
            + "]";
    }

	/* SugarCube support */
    clone () {
        return Stat.create(this);
    }

	toJSON () {
        return JSON.reviveWrapper('Stat.create($ReviveData$)', Object.assign({}, clone(this)));
    }
};

Stat.create = function(vals) {
    vals = vals || {};
    var result = new Stat();
    result._base = vals._base;
    result._mods = clone(vals._mods);
    result._current = vals._current;
    return result;
};

Map.prototype.addMod = function (key, id, mod, equipment) {
	return this.get(key).addMod(id,mod,equipment);
}

Map.prototype.removeMod = function (key, id, index) {
	this.get(key).removeMod(id, index);
}

----

class Effect {
constructor(name,time,power,target){
		this.name = name;
		(...)

		switch (name) {
			case 'ATK Boost':
				this.buff = true;
				this.stackable = true;
				this.statmod = true;
				this.onApply = (puppet) => {
					this.id = puppet.stats.addMod("Attack","ATK Boost",this.power);
					console.log("Applying ATK Boost. ID = "+this.id);
				}
				this.onRemove = (puppet) => {
					console.log("Removing ATK Boost. ID = "+this.id);
					puppet.stats.removeMod("Attack","ATK Boost",this.id);
				}
				this.info = function () {
					return `Attack boosted by ${this.power}.`;
				}
				this.addText = function (target) {
					return `${target} is surging with strength!`;
				}
				this.removeText = remBuff;
				break;
}
}