Implementing auto-population of input field in Vue JS based on dropdown selection

Question

Implementing auto-population of input field in Vue JS based on dropdown selection

I'm in search of a solution for automatically filling input fields in Vue.js. My form consists of various input types such as text, select dropdowns, and quantities. I want the vCPU, vRAM, and Storage Capacity fields to be filled with predefined values based on the selected Server Flavor from the dropdown.

For example, when selecting 'Flavor 1', the vCPU should display 4, vRAM should show 2, and storage capacity should be 10. However, the quantity field is not updating accordingly.

In the price estimation section, the correct numbers are displayed: vCPU (4), vRAM (2), Storage Capacity (10).

I am uncertain whether I should implement the if conditionals in the <base-quantity> component during the @updateQuantity custom event or within the v-if attribute. Can anyone assist me in resolving this issue?

The full source code can be found on this codesandbox: https://codesandbox.io/s/suspicious-almeida-rjyy9

Lite.vue

<template>
    <div class="container">
        <h2 class="font-size-26 txt-secondary">Deka Flexi</h2>
        <!-- Rest of the Lite.vue template code goes here -->
    </div>
</template>

<script>
// Lite.vue script content including data, watch, methods
</script>

BaseQuantity.vue

<template>
    <div class="quantity" :class="disabled ? 'quantity__untoggle' : 'quantity__toggle'">
        <button type="button" @click="decrement" class="btn quantity__decrement" :disabled="disabled">-</button>
        <input type="text" class="quantity__value" :value="quantity" :disabled="disabled" readonly>
        <button type="button" @click="increment" class="btn quantity__increment" :disabled="disabled">+</button>
    </div>
</template>

<script>
// BaseQuantity.vue script content
</script>

javascript vue.js vuejs3

Answer 1

Answer №1

To manage your data effectively, it's crucial to consider how it is stored and interconnected across components.

Let's begin with BaseQuantity.vue:

data() {
  return {
    quantity: 0 // local state for the quantity
  }
},
methods: {
  increment() {
    this.quantity++ // update the LOCAL state when the user interacts
  },
}
watch: {
  quantity: function(val) { // when the LOCAL value changes
    this.$emit('updateQuantity', val); // emit event signaling the update
  }
}

In essence, each Base Quantity component sets its own state (initially at 0) and tracks actions that alter that state.

These components are utilized like

<base-quantity @updateQuantity="updateServer"

This method then calls upon Vuex to store the new value received from the component's internal state:

updateServer(val) {
  this.$store.commit('setServer', {qty: val, value: 100});
}

The initial challenge lies in each Base Quantity component defining its exclusive initial state internally. At present, there isn't a direct way for these components to indicate their respective values, rather they inform the parent about updates.

To address this, you need to set the initial value somehow. A fundamental approach would involve passing the initial value to the component:
```
props : ['disabled', 'initialValue'],
data(){
  return {
    quantity: this.initialValue
  }
},
```
The subsequent issue involves not only having an initial value but also being able to dynamically set external values whenever a user selects a dropdown option. This necessitates a bidirectional binding of values—a scenario where v-model proves beneficial. Here's a helpful article explaining its implementation: https://v3-migration.vuejs.org/breaking-changes/v-model.html#overview. You can employ it as shown below:
```
<base-quantity v-model="serverQuantity" />



<base-quantity
  :modelValue="serverQuantity"
  @update:modelValue="serverQuantity= $event"
/>
```
You should not store data within your Calculator component but in Vuex. The design of your data flow holds various solutions, and careful consideration must be given. A recommended simple approach includes:
- Utilize store getters to instruct Base Quantity on its value:
```
<base-quantity :value="$store.getters.serverQuantity" />
```
  . This reactive property will update when the store modifies its server quantity value. If getters aren't available, using the state directly is discouraged.
- Eliminate the local variable for quantity and rely on the passed property instead:
```
<input :value="value" />
```
- Upon update (e.g., button click), emit an event with the new value without local modification:
```
increment() { this.$emit('updateQuantity', this.value + 1)
```
- In your handler, commit the update accordingly

To handle dropdown selections based on the aforementioned approach, simply await user input (dropdown selection) and populate the store with required fields. As these values are passed to each component, the auto-population occurs seamlessly:
```
qty: val, value: 100 throughout isn't entirely clear, likely serving a purpose.
```

Adopting this strategy ensures a singular source of truth regarding data, with components simply requesting modifications to values without delving into business logic or storage specifics. The parent manages both data transmission to components and oversees user actions, subsequently committing changes to a centralized Vuex store.

Answer 2

To manage your data effectively, it's crucial to consider how it is stored and interconnected across components.

Let's begin with BaseQuantity.vue:

data() {
  return {
    quantity: 0 // local state for the quantity
  }
},
methods: {
  increment() {
    this.quantity++ // update the LOCAL state when the user interacts
  },
}
watch: {
  quantity: function(val) { // when the LOCAL value changes
    this.$emit('updateQuantity', val); // emit event signaling the update
  }
}

In essence, each Base Quantity component sets its own state (initially at 0) and tracks actions that alter that state.

These components are utilized like

<base-quantity @updateQuantity="updateServer"

This method then calls upon Vuex to store the new value received from the component's internal state:

updateServer(val) {
  this.$store.commit('setServer', {qty: val, value: 100});
}

The initial challenge lies in each Base Quantity component defining its exclusive initial state internally. At present, there isn't a direct way for these components to indicate their respective values, rather they inform the parent about updates.

To address this, you need to set the initial value somehow. A fundamental approach would involve passing the initial value to the component:
```
props : ['disabled', 'initialValue'],
data(){
  return {
    quantity: this.initialValue
  }
},
```
The subsequent issue involves not only having an initial value but also being able to dynamically set external values whenever a user selects a dropdown option. This necessitates a bidirectional binding of values—a scenario where v-model proves beneficial. Here's a helpful article explaining its implementation: https://v3-migration.vuejs.org/breaking-changes/v-model.html#overview. You can employ it as shown below:
```
<base-quantity v-model="serverQuantity" />



<base-quantity
  :modelValue="serverQuantity"
  @update:modelValue="serverQuantity= $event"
/>
```
You should not store data within your Calculator component but in Vuex. The design of your data flow holds various solutions, and careful consideration must be given. A recommended simple approach includes:
- Utilize store getters to instruct Base Quantity on its value:
```
<base-quantity :value="$store.getters.serverQuantity" />
```
  . This reactive property will update when the store modifies its server quantity value. If getters aren't available, using the state directly is discouraged.
- Eliminate the local variable for quantity and rely on the passed property instead:
```
<input :value="value" />
```
- Upon update (e.g., button click), emit an event with the new value without local modification:
```
increment() { this.$emit('updateQuantity', this.value + 1)
```
- In your handler, commit the update accordingly

To handle dropdown selections based on the aforementioned approach, simply await user input (dropdown selection) and populate the store with required fields. As these values are passed to each component, the auto-population occurs seamlessly:
```
qty: val, value: 100 throughout isn't entirely clear, likely serving a purpose.
```

Adopting this strategy ensures a singular source of truth regarding data, with components simply requesting modifications to values without delving into business logic or storage specifics. The parent manages both data transmission to components and oversees user actions, subsequently committing changes to a centralized Vuex store.

Answer 3

Answer №2

In this particular case, the v-model method may not be suitable for setting values based on selected events. To address this issue, a custom function can be created to handle value assignment.

Here is an example of how you can achieve this:

updateValues: function () {
      if (this.selectedOption === 'option 1') {
        this.value = 'Option 1 selected';
      } else {
        this.value = '';
      }
}

This approach can also be applied to other variables such as Databases, StorageType, and Firewall settings.

Answer 4

In this particular case, the v-model method may not be suitable for setting values based on selected events. To address this issue, a custom function can be created to handle value assignment.

Here is an example of how you can achieve this:

updateValues: function () {
      if (this.selectedOption === 'option 1') {
        this.value = 'Option 1 selected';
      } else {
        this.value = '';
      }
}

This approach can also be applied to other variables such as Databases, StorageType, and Firewall settings.

Implementing auto-population of input field in Vue JS based on dropdown selection

Answer №1

Answer №2

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