Difficulty arising from implementing v-if as a filter within a v-for loop in Vue.js

Question

Difficulty arising from implementing v-if as a filter within a v-for loop in Vue.js

I'm struggling a bit with setting up a conditional statement using v-if along with a loop using v-for in Vue. Here's what I have so far:

<div class="row form-group" v-for="(article, key, index) in articles" :key="key" v-if="article.pubdate(first four characters)">={{ filterYear}} >

I'm unsure of how to extract the first four characters from the pubdate and treat it as a number, as well as how to pass in the filterYear. The data structure for articles is JSON returned via Axios. However, the format of pubdate is: year, space, then month (e.g., 2007 Aug or 2009 Aug 1).

My goal is to isolate a year and use it within the v-if, displaying only articles written during or after that specific year. I also have similar functionality on the JavaScript side where values are identified and converted into a string (uid_string). Check out this example on CodePen.

javascript vue.js vuejs2

Answer 1

Answer №1

One way to simplify the loop filter instead of using a v-if condition is by utilizing a computed property. This method not only streamlines the template for the loop but also eliminates the need for extra calculations to determine the ordinal number for each item, as the index of the array can naturally serve as the ordinal number.

For instance, you can integrate the suggested filter from @Stephen into a computed property:

<script>
export default {
  computed: {
    filteredArticles() {
      const { articles, filterYear } = this
      return Object.values(articles)
        .filter(article => parseInt(article.pubdate.substring(0,4)) >= filterYear)
    }
  }
}
</script>

After defining the computed property, simply utilize it in your template like so:

<template>
  <div v-for="(article, index) in filteredArticles" :key="article.uid">
   ...
  </div>
</template>

To see a demonstration of this approach, check out this demo.

Answer 2

One way to simplify the loop filter instead of using a v-if condition is by utilizing a computed property. This method not only streamlines the template for the loop but also eliminates the need for extra calculations to determine the ordinal number for each item, as the index of the array can naturally serve as the ordinal number.

For instance, you can integrate the suggested filter from @Stephen into a computed property:

<script>
export default {
  computed: {
    filteredArticles() {
      const { articles, filterYear } = this
      return Object.values(articles)
        .filter(article => parseInt(article.pubdate.substring(0,4)) >= filterYear)
    }
  }
}
</script>

After defining the computed property, simply utilize it in your template like so:

<template>
  <div v-for="(article, index) in filteredArticles" :key="article.uid">
   ...
  </div>
</template>

To see a demonstration of this approach, check out this demo.

Answer 3

Answer №2

If you want to extract an integer year from the first four characters:

parseInt(article.pubdate.substring(0, 4))

<div  
v-for="(article, key, index) in articles" 
:key="key" 
v-if="parseInt(article.pubdate.substring(0, 4))>=filterYear">

Your code goes here... 
To display the article JSON, use curly braces: {{article}}.
Similarly for the date {{article.date}}, etc.
Avoid using curly braces within template attributes.

</div>

An advantage of Vue is that all template properties are relative to the component, eliminating the need to use this. as a reference.

To tidy up the template, consider moving the parseInt(...) and comparison logic to a component method.

You can see these changes in action on your updated codepen: https://codepen.io/anon/pen/NVrvre?editors=1111

Answer 4

If you want to extract an integer year from the first four characters:

parseInt(article.pubdate.substring(0, 4))

<div  
v-for="(article, key, index) in articles" 
:key="key" 
v-if="parseInt(article.pubdate.substring(0, 4))>=filterYear">

Your code goes here... 
To display the article JSON, use curly braces: {{article}}.
Similarly for the date {{article.date}}, etc.
Avoid using curly braces within template attributes.

</div>

An advantage of Vue is that all template properties are relative to the component, eliminating the need to use this. as a reference.

To tidy up the template, consider moving the parseInt(...) and comparison logic to a component method.

You can see these changes in action on your updated codepen: https://codepen.io/anon/pen/NVrvre?editors=1111

Difficulty arising from implementing v-if as a filter within a v-for loop in Vue.js

Answer №1

Answer №2

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