Mapped getters are undefined

Question

I've mapped a set of getters into my component and am trying to call them with a parameter in methods, however the getters are coming up as undefined. I've mapped them following an answer on a previous question

computed: {
    ...mapGetters([
        'products/getCategoryProducts', 
        'categories/getSubcategories', 
        'categories/getCategory'
    ]),

    products () {
        return this['products/getCategoryProducts'](this.id)
    },

    subCategories () {
        return this['categories/getSubcategories'](this.id)
    },

    category () {
        return this['categories/getCategory'](this.id)
    },
}

The error being:

TypeError: this.categories/getCategory is not a function

I've console logged this:

Edit: Updated code following @Luceos answer:

computed: {
    ...mapGetters({
        getProducts: 'products/getCategoryProducts', 
        getSubCategories: 'categories/getSubcategories', 
        getCategory: 'categories/getCategory'
    }),

    products () {
        return this.getProducts(this.id)
    },

    subCategories () {
        return this.getSubCategories(this.id)
    },

    category () {
        return this.getCategory(this.id)
    },
}

Which returns:

TypeError: this.getCategory is not a function

My getter:

getCategory: (state, id) => {
    return state.categories.filter(category => category.id === id);
}

Answer 1

Try this:

computed: {
    ...mapGetters({
        products: 'products/getCategoryProducts', 
        subcategories: 'categories/getSubcategories', 
        category: 'categories/getCategory'
    }),

    products () {
        return this.products(this.id)
    },

    subCategories () {
        return this.subcategories(this.id)
    },

    category () {
        return this.category(this.id)
    },
}

And your getters should be functions expecting the id for example:

getCategory: (state) => (id) => {
    return state.categories.filter(category => category.id === id);
}

Make sure to take a look at docs Method-Style Access