Is it possible to alter a computed property in Vue.js?

Question

Is it possible to alter a computed property in Vue.js?

In my quest to modify a moment.js instance housed in a vue.js computed property, I have encountered a challenge.

computed: {
    currentDate() {
        return moment();
    }
}

Attempting to update it with a method like this one has proved ineffective:

methods: {
    prevMonth() {
        this.currentDate = moment(this.currentDate).subtract(1, 'months');
    }
}

This issue seems to be rooted in the fact that computed properties only function as getters (and potentially setters). How can I alter this behavior?

I simplified the example, as I utilize the computed property for data retrieval from my vuex store. Unfortunately, manipulating it is now proving challenging.

Is there a way to populate a local currentDate property with the value from the vuex store so I can continue modifying it by adding months and more?

I considered using the mounted property for this purpose, but since I only mount my component once, it may not be suitable. Any guidance on this issue would be greatly appreciated.

javascript vue.js vuejs2 vue-component vuex

Answer 1

Answer №1

When managing the currentDate property in your Vuex store, it's important to avoid manipulating it directly within your components. Instead, follow these steps: 1) map the getter as a computed property locally and 2) map the mutation as a method locally.

Consider this example implementation of a date Vuex module:

export default {
    state: {
        currentDate: moment()
    },
    mutations: {
        subtractMonth (state, date) {
            state.currentDate = moment(state.currentDate).subtract(1, 'months');
        }
    },
    getters: {
        getCurrentDate: (state) => {
            return state.currentDate
        }
    }
}

This is how you can utilize the Vuex module in your component without direct manipulation:

import { mapGetters, mapMutations } from 'vuex'
export default {
    computed: {
        ...mapGetters({
            currentDate: 'getCurrentDate'
        })
    },
    methods: {
        ...mapMutations({
            prevMonth: 'subtractMonth'
        })
    }
}

You can still bind currentDate in your component and call prevMonth, but now all operations are centralized through the Vuex state management system.

Answer 2

When managing the currentDate property in your Vuex store, it's important to avoid manipulating it directly within your components. Instead, follow these steps: 1) map the getter as a computed property locally and 2) map the mutation as a method locally.

Consider this example implementation of a date Vuex module:

export default {
    state: {
        currentDate: moment()
    },
    mutations: {
        subtractMonth (state, date) {
            state.currentDate = moment(state.currentDate).subtract(1, 'months');
        }
    },
    getters: {
        getCurrentDate: (state) => {
            return state.currentDate
        }
    }
}

This is how you can utilize the Vuex module in your component without direct manipulation:

import { mapGetters, mapMutations } from 'vuex'
export default {
    computed: {
        ...mapGetters({
            currentDate: 'getCurrentDate'
        })
    },
    methods: {
        ...mapMutations({
            prevMonth: 'subtractMonth'
        })
    }
}

You can still bind currentDate in your component and call prevMonth, but now all operations are centralized through the Vuex state management system.

Answer 3

Answer №2

Remember, computed properties are different from methods - they cannot be called directly. If you need a method instead, consider moving the logic for currentDate into a method that can then be invoked within the mounted hook.

Answer 4

Remember, computed properties are different from methods - they cannot be called directly. If you need a method instead, consider moving the logic for currentDate into a method that can then be invoked within the mounted hook.

Is it possible to alter a computed property in Vue.js?

Answer №1

Answer №2

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