Vue.js explained through Pokemon #5

Damage-calculateTypeEffect.js

    // Consult the type chart and build a multiplier
    calculateTypeEffect(otherPokemonType) {
        // If we haven't defined the type in the typeChart return normal damage
        if (typeof this.typeChart[this.attack.type] == 'undefined')
            return 1;

        // Here we'll build the multiplier in
        let effectTotal = 1;

        // In case of immune we'll just set this to true
        let noEffect = false;

        // Let's loop over every type the defending pokemon has
        this.defending.type.forEach((type) => {

            // Let's loop offer the effects that attack type has on other types
            Object.keys(this.typeChart[this.attack.type]).forEach((effect) => {
                const otherTypes = this.typeChart[this.attack.type][effect];

                // If the effect has types defined and the defending pokemon's type is listed
                if(otherTypes.length > 0 && otherTypes.indexOf(type) > -1)
                {
                    // Figure out what effect to apply
                    switch(effect)
                    {
                        case 'immunes':
                            noEffect = true;
                            effectTotal = 0;
                            break;
                        // Reduce the attack's damage
                        case 'weaknesses':
                            effectTotal = effectTotal * 0.5;
                            break;
                        // Increase the attack's effect
                        case 'strengths':
                            if(effectTotal < 2)
                                effectTotal = effectTotal * 2;
                            break;
                    }
                }
            }, this);
        });

        // Defending pokemon is immune
        if (noEffect || effectTotal == 0)
        {
            Vuemit.fire(otherPokemonType+'.attack.effective', 'Had no effect');
            return 0;
        }

        if(effectTotal == 0.5)
        {
            Vuemit.fire(otherPokemonType+'.attack.effective', 'Not very effective');
        }
        else if(effectTotal > 1)
        {
            Vuemit.fire(otherPokemonType+'.attack.effective', 'Very effective');
        }

        // Return the multiplier
        return effectTotal;
    }