Vue Deep Watching An Array Of Objects And Calculating The Change

Have you ever worked on a project using Vue.js and needed to keep track of changes in an array of objects? Perhaps you found yourself stuck when trying to calculate the difference between the old and new values? Well, fear not, as today we're delving into the technique of deep watching an array of objects in Vue.js and effectively calculating those changes.

When dealing with complex data structures like arrays of objects in Vue.js, the reactivity system might not catch changes made deep within these objects automatically. This is where deep watchers come into play. Deep watchers allow Vue.js to watch changes that occur within nested data structures and respond accordingly.

To deep watch an array of objects and accurately calculate the change, we can use a combination of Vue's watch functionality along with the lodash library. Lodash provides a variety of utility functions for working with arrays and objects, making it a valuable tool in this scenario.

Firstly, ensure that you have lodash installed in your project by running the following command:

npm install lodash

Once lodash is added to your project dependencies, you can import it into your Vue component where you need to deep watch the array of objects:

import _ from 'lodash';

Next, let's set up the watch function in your Vue component to monitor the changes in the array of objects:

watch: {
  'myArrayOfObjects': {
    handler: function (newVal, oldVal) {
      const difference = _.isEqual(newVal, oldVal) ? 'No change' : 'Changes detected';      
      console.log(difference);
    },
    deep: true
  }
}

In the code snippet above, we're watching the 'myArrayOfObjects' property of the component. The 'handler' function takes two arguments - 'newVal' and 'oldVal', representing the new and old values of the array of objects, respectively. We then use lodash's isEqual function to compare the new and old values. If they are equal, we log 'No change'; otherwise, we log 'Changes detected'.

By setting 'deep: true', Vue.js will recursively traverse the properties of the array of objects to detect changes, ensuring that nested changes are captured as well.

Now, whenever a change occurs within the array of objects, our watch function will be triggered, and you'll be able to see whether any modifications took place.

Deep watching an array of objects in Vue.js and accurately calculating the change is a powerful technique that can streamline your development process and help you maintain data integrity within your applications. By combining Vue's reactivity system with lodash's utility functions, you can ensure that changes within nested data structures are properly monitored and handled.

So, the next time you find yourself working with complex data structures in Vue.js, remember to leverage deep watchers to keep track of those changes effectively. Happy coding!