Looping precisely five times in Vue3JS over an array and conditionally verifying each element within

Question

Looping precisely five times in Vue3JS over an array and conditionally verifying each element within

After spending the past 2 hours searching through similar subjects on SO without success, I am turning to you for help.

My goal is to create a scoreboard displaying results in the following format:

John Doe 100 pts
John Smith 50 pts
No Name
No Name
No Name

I have an array named scoreBoardArray containing the necessary data.

data() {
  return {
     scoreBoardArray: [
        { id: '1', name: 'John Doe', pts: 100 },
        { id: '2', name: 'John Smith', pts: 50 },
     ],
   }
},

I have attempted to loop through this array and display the names and points exactly 5 times, filling in with "No Name" when no record is found.

This is my code (and attempts to solve the issue):

<ul>
   <li v-for="item in scoreBoardArray" :key="item.id">
      <span v-if="item.id">{{ item.name }} {{ item.pts }}</span>. 
      <span v-else>No Name</span>
   </li>
</ul>

Despite trying to use a computed property and a basic loop like for(let i=0; i<6; i++) {...}, I haven't been successful in solving the issue.

javascript arrays loops vue.js vuejs3

Answer 1

Answer №1

To extract the first 5 elements in the scoreBoardArray[] and determine how many "No Name" dummy items are required, you can utilize a computed property named topScores for the top scores and dummyLength to calculate the number of dummy items needed:

export default {
  computed: {
    topScores() {
      return this.scoreBoardArray
        .slice()                      // create a copy
        .sort((a,b) => b.pts - a.pts) // sort by points
        .slice(0, 5)                  // get first 5 elements
    },
    dummyLength() {
      return Math.max(0, 5 - this.topScores.length)
    }
  }
}

Update the template to display the computed properties using a v-for, showing the topScores followed by dummyLength for the dummy items:

<ul>
  <li v-for="item in topScores" :key="item.id">
    <span>{{ item.name }} ({{ item.pts }})</span>
  </li>
  <li v-for="n in dummyLength">No Name</li>
</ul>

Check out the demo.

Answer 2

To extract the first 5 elements in the scoreBoardArray[] and determine how many "No Name" dummy items are required, you can utilize a computed property named topScores for the top scores and dummyLength to calculate the number of dummy items needed:

export default {
  computed: {
    topScores() {
      return this.scoreBoardArray
        .slice()                      // create a copy
        .sort((a,b) => b.pts - a.pts) // sort by points
        .slice(0, 5)                  // get first 5 elements
    },
    dummyLength() {
      return Math.max(0, 5 - this.topScores.length)
    }
  }
}

Update the template to display the computed properties using a v-for, showing the topScores followed by dummyLength for the dummy items:

<ul>
  <li v-for="item in topScores" :key="item.id">
    <span>{{ item.name }} ({{ item.pts }})</span>
  </li>
  <li v-for="n in dummyLength">No Name</li>
</ul>

Check out the demo.

Answer 3

Answer №2

If you need to expand your array to a specific length, consider using a computed property.

One approach is to add empty objects to the end of your array until it reaches 5 values.

computed: {
  expandedArray() {
    let padding = []
    const paddingCount = 5 - this.originalArray.length
    for (let i = 0; i < paddingCount; i++) {
      padding[i] = {}
    }
    return [...this.originalArray, ...padding]
  }
}

Keep in mind that when adding empty objects, you may face issues with v-for loop keys. To address this, consider using indices as keys:

<li v-for="(item, index) in expandedArray" :key="index">

Answer 4

If you need to expand your array to a specific length, consider using a computed property.

One approach is to add empty objects to the end of your array until it reaches 5 values.

computed: {
  expandedArray() {
    let padding = []
    const paddingCount = 5 - this.originalArray.length
    for (let i = 0; i < paddingCount; i++) {
      padding[i] = {}
    }
    return [...this.originalArray, ...padding]
  }
}

Keep in mind that when adding empty objects, you may face issues with v-for loop keys. To address this, consider using indices as keys:

<li v-for="(item, index) in expandedArray" :key="index">

Looping precisely five times in Vue3JS over an array and conditionally verifying each element within

Answer №1

Answer №2

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