Is it possible to use null in Vue computed properties to monitor changes in the data?

I am trying to leverage Vue's computed property to detect changes in multiple pieces of data and automatically execute a function. However, I only want to use computed as a function without generating any new values.

It seems that computed properties do not get executed automatically unless they are used directly. To work around this, I have decided to return null from the computed function and then call it using {{}} in the template tag. Is this the correct approach? I am trying to avoid using watch whenever possible.

Additionally, I am wondering if it is possible to define a process in my "afterRendering" method which does not return anything, and then force it to be called using {{afterRendering}} after each render.

<template>
...
{{afterRendering()}} <!--this will run after every render.-->
{{MyComputed}} <!--this will run when there are changes in dependent bindings.-->

</template>
...
export default {
  methods: {
    afterRendering: function () {
      // Define the process here
    },
  },
  computed: {
    MyComputed: function () {
      if (!!Achanged || !!Bchanged) {
        // Check for changes in A and B here
        return null
      }
    },
  },
}

Answer №1

Instead of utilizing your afterRendering function, you can opt for the built-in mounted() function within Vue.js. Another option is to use the updated() lifecycle hook if you need a function to run on every re-render. For more information, refer to the documentation here, and check out the Vue lifecycle diagram here. Additionally, it is possible to utilize computed properties in this manner; just be cautious of any side effects such as assigning values to data properties.

Answer №2

While this may not be the exact solution the original poster was seeking, I believe it presents a viable alternative approach to address the issue at hand.

export default {
    watch: {
        ...['x', 'y', 'z', 'm', 'n'].reduce((obj, currentValue) => {
            obj[currentValue] = {
                handler: () => {
                    // Perform necessary actions
                },
                immediate: true,
            };

            return obj;
        }, {})
    }
}

To avoid repeating code, one could utilize a reduce function with the variables containing the arrays. By employing array destructuring, the same function can be assigned to all variables, enhancing code clarity and simplifying comprehension when making modifications to the watch handler.

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