How to retrieve the length of an array using

Question

How to retrieve the length of an array using

Currently, I am deepening my understanding in javascript and exploring the vue.js 3 composition API. I have a specific question regarding retrieving the length of an array and displaying it within a <p> tag. The array in question is named "getForms".

<script>.....
const forms_length = computed(() => getForms.value.length)

<template>....
<p> {{form_length}} </p>

After implementing this code snippet, I encountered an error message: "Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'length')"

Could you please explain why this error occurs and what steps should be taken to resolve it?

Your assistance on this matter would be greatly appreciated. Thank you!

javascript arrays vue.js vue-composition-api

Answer 1

Answer №1

Check out this example of using the computed property:

<template>
  <p>Total items in array: {{ itemTotal }}</p>
</template>
<script>
  import { computed } from 'vue'
  import { useItemsStore } from '../store/items' 
  setup() {
    const { store } = useItemsStore()
    
   // If the store.items array is not defined or ready, it will return an empty array
    const getItems = computed(() => { return store.items || []})
  
    // Using computed property to calculate the length of the array
    const itemTotal = computed(() => getItems.value.length)

    return {
      itemTotal
    }
  }
</script>

Answer 2

Check out this example of using the computed property:

<template>
  <p>Total items in array: {{ itemTotal }}</p>
</template>
<script>
  import { computed } from 'vue'
  import { useItemsStore } from '../store/items' 
  setup() {
    const { store } = useItemsStore()
    
   // If the store.items array is not defined or ready, it will return an empty array
    const getItems = computed(() => { return store.items || []})
  
    // Using computed property to calculate the length of the array
    const itemTotal = computed(() => getItems.value.length)

    return {
      itemTotal
    }
  }
</script>

How to retrieve the length of an array using

Answer №1

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