What is the best way to create a non-reactive value in Vue.js?

Question

What is the best way to create a non-reactive value in Vue.js?

In my Vue.js app, I am facing an issue where an array value is becoming reactive even though I want it to remain un-reactive. The array should only be updated when a specific "refresh" action is completed. However, every time a new value is assigned to the array, it immediately changes in reaction to the data in the assigned value.

For instance, let's say I have a method called refresh(). This method is supposed to update displayedData (which should not be reactive) with the data from currentData (which should be reactive). The goal is to have displayedData only update when the refresh method is called.

methods: {
    refresh: function() {
        this.displayedData = this.currentData;
    }
}

javascript vue.js vuejs2 vuejs3

Answer 1

Answer №1

To prevent reactivity without making a value static, you can create a "deep copy" using the stucturedClone() method, which has universal support as of early 2022:

this.displayedData = structuredClone(this.currentData);

Prior to structuredClone(), a common method used involved encoding and decoding with JSON:

this.displayedData = JSON.parse(JSON.stringify(this.currentData));

Both approaches copy the current state of one value to another, ensuring that changes to the original value do not affect the copied value until this code is executed again. Nonetheless, structeredClone() is preferable for various reasons.

The need for this process is not unique to Vue.js but stems from the nature of JavaScript. In JavaScript, arrays and objects are "passed by reference" rather than "passed by value".

Answer 2

To prevent reactivity without making a value static, you can create a "deep copy" using the stucturedClone() method, which has universal support as of early 2022:

this.displayedData = structuredClone(this.currentData);

Prior to structuredClone(), a common method used involved encoding and decoding with JSON:

this.displayedData = JSON.parse(JSON.stringify(this.currentData));

Both approaches copy the current state of one value to another, ensuring that changes to the original value do not affect the copied value until this code is executed again. Nonetheless, structeredClone() is preferable for various reasons.

The need for this process is not unique to Vue.js but stems from the nature of JavaScript. In JavaScript, arrays and objects are "passed by reference" rather than "passed by value".

Answer 3

Answer №2

To simplify your code, try using destructuring assignment: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment?retiredLocale=fr

this.newData = {...this.originalData}

You can create a new object containing the same data as the original one

Answer 4

To simplify your code, try using destructuring assignment: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment?retiredLocale=fr

this.newData = {...this.originalData}

You can create a new object containing the same data as the original one

Answer 5

Answer №3

One way to approach this issue without turning off reactivity is to create a separate array for temporary data and transfer the contents to the main array when the user refreshes the page.

To achieve this, you can simply copy the values from the main array to the temporary array using the following code:

this.temp = this.permanent.slice()

within the created or mounted life-cycle function.

Keep in mind that using the slice method creates a shallow copy of the array. If you also need to clone the items within the array, consider using a deep copy library or the JSON.parse(JSON.stringify(...)) method.

Answer 6

One way to approach this issue without turning off reactivity is to create a separate array for temporary data and transfer the contents to the main array when the user refreshes the page.

To achieve this, you can simply copy the values from the main array to the temporary array using the following code:

this.temp = this.permanent.slice()

within the created or mounted life-cycle function.

Keep in mind that using the slice method creates a shallow copy of the array. If you also need to clone the items within the array, consider using a deep copy library or the JSON.parse(JSON.stringify(...)) method.

Answer 7

Answer №4

Not adding the currentData to the data() method will result in it not being reactive.

export default {
    currentData: [],
    data() {
        return {

        }
    },
    methods: {
        refresh: function() {
            this.displayedData = this.currentData;
        }
    }
}

To still access currentData in the section, you can use {{ $options.currentData }}

Answer 8

Not adding the currentData to the data() method will result in it not being reactive.

export default {
    currentData: [],
    data() {
        return {

        }
    },
    methods: {
        refresh: function() {
            this.displayedData = this.currentData;
        }
    }
}

To still access currentData in the section, you can use {{ $options.currentData }}

What is the best way to create a non-reactive value in Vue.js?

Answer №1

Answer №2

Answer №3

Answer №4

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