How to use model directive with two way computed property? 180

 How to use model directive with two way computed property?

There are two main approaches to using the v-model directive with a two-way computed property in Vue.js:

1. Using a setter in the computed property:

This approach leverages the setter function provided by the computed property. Here's how it works:

HTML

<input v-model="computedValue" @input="$refs.input.focus()" />

JavaScript

export default {
  computed: {
    computedValue: {
      get() {
        // Return the desired state value here
        return this.originalStateValue;
      },
      set(newValue) {
        // Update the original state value based on newValue
        this.originalStateValue = newValue;
        // Emit custom event or dispatch action if needed
        this.$emit('update-value', newValue);
      },
    },
  },
  data() {
    return {
      originalStateValue: "Initial value", // replace with your initial state
    };
  },
};

In this example:

• The v-model directive binds the input field to the computedValue property.

• The computedValue property has a getter and a setter.

• The getter returns the current state value.

• The setter updates the originalStateValue based on the new value received from the input field.

• You can optionally emit a custom event or dispatch an action within the setter to notify other components about the state change.

2. Using a separate data property:

This approach involves creating a separate data property alongside the computed property to act as the actual state being bound by v-model. Here's how it works:

HTML

<input v-model="inputState" @input="$refs.input.focus()" />

JavaScript

export default {
  computed: {
    computedValue: {
      get() {
        // Your logic to compute the displayed value based on inputState
        return someTransformation(this.inputState);
      },
    },
  },
  data() {
    return {
      inputState: "Initial value", // replace with your initial state
    };
  },
};

In this example:

• The v-model directive binds the input field to the inputState data property.

• The computedValue property uses the inputState to calculate and represent the displayed value using your chosen logic.

• Any changes to the input field update the inputState directly, triggering the recalculation of the computedValue and reflecting the change in the UI.

Choosing the right approach:

• The first approach is more concise and avoids introducing an additional data property. However, it can be less intuitive for complex logic and handling side effects.

• The second approach is more explicit and easier to understand when dealing with intricate computations or additional actions triggered by state changes.

Ultimately, the best approach depends on your specific needs and the complexity of your logic. Choose the one that makes your code cleaner, more readable, and easier to maintain for your project.

Remember, both approaches ensure two-way data binding between the input field and the state managed by the computed property or additional data property. However, they differ slightly in their structure and handling of updates.

Feel free to ask further questions if you need help adapting these approaches to your specific scenario, implementing them in your code, or choosing the best fit for your requirements!