How to properly distinguish between v-if and v-for in Vue.js 3

Question

How to properly distinguish between v-if and v-for in Vue.js 3

I recently came across a discussion stating that combining v-if and v-for in Vue.js is not recommended. I encountered an error in my IDE while attempting to use both together. Can someone guide me on how to properly separate the v-if and v-for directives in my code to align with the style guide?

<div
        v-for="(value, key, index) in items"
        v-if="value.level === undefined || value.level < level"
        :key="key"
      >

The 'level' value is also calculated as computed property

computed: {
    level() {
      return (
         user.access>3
      );
    }
  },

javascript vue.js vuejs2 vuejs3 v-for

Answer 1

Answer №1

For a clever way to control rendering, consider using an invisible wrapper called the <template> element with v-if. This allows the template contents to remain hidden until the specified condition is met. If you're curious to learn more about this technique, check out the documentation on templates here

Here's an example:

<div v-for="(value, key, index) in items" :key="key">
  <template v-if="value.level === undefined || value.level < level"> // It won't render until v-if = true
   ....

Answer 2

For a clever way to control rendering, consider using an invisible wrapper called the <template> element with v-if. This allows the template contents to remain hidden until the specified condition is met. If you're curious to learn more about this technique, check out the documentation on templates here

Here's an example:

<div v-for="(value, key, index) in items" :key="key">
  <template v-if="value.level === undefined || value.level < level"> // It won't render until v-if = true
   ....

Answer 3

Answer №2

Ensure to place the v-if directive within a "template" virtual element:


<div   v-for="(val, k, idx) in list" :key="k">
   <template v-if="val.grade === undefined || val.grade < threshold">
    ....

Answer 4

Ensure to place the v-if directive within a "template" virtual element:


<div   v-for="(val, k, idx) in list" :key="k">
   <template v-if="val.grade === undefined || val.grade < threshold">
    ....

Answer 5

Answer №3

To avoid cluttering the DOM with unnecessary divs, make sure to filter it out.

computed: {
   refined_items: function() {
     return this.items.filter(value => typeof value.rank === 'undefined' || value.rank < this.rank)
   }
},

Substitute refined_items for items when using v-for loop

An alternative is to filter inline:

v-for="element in items.filter(value => typeof value.rank === 'undefined' || value.rank < rank)"

Answer 6

To avoid cluttering the DOM with unnecessary divs, make sure to filter it out.

computed: {
   refined_items: function() {
     return this.items.filter(value => typeof value.rank === 'undefined' || value.rank < this.rank)
   }
},

Substitute refined_items for items when using v-for loop

An alternative is to filter inline:

v-for="element in items.filter(value => typeof value.rank === 'undefined' || value.rank < rank)"

How to properly distinguish between v-if and v-for in Vue.js 3

Answer №1

Answer №2

Answer №3

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