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I have an array containing data of questions that will be displayed. Only one question must be displayed at a time. Once the user selects an answer to a question, they can move to the next one by, either, the click of a button or using the up and down arrow keys.

Here’s a gif of the present version:
Screen recording gif

The App.vue file:

import { defineComponent, ref } from 'vue';
import QuestionCard from "./components/QuestionCard.vue";

export default defineComponent({
   components: {
      QuestionCard
   },
   setup() {
      const questionArray = ref([
         {
            id: "123",
            question: "Which of these is a colour in the rainbow?",
            options: [
               'brown', 'red', 'black',
            ],
         }, {
            id: "456",
            question: "How many continents does Earth have?",
            options: [
               1, 7, 6, 9
            ],
         }, {
            id: "789",
            question: "Which of these is a prime number?",
            options: [
               7, 4, 44, 
            ],
         },
      ]);

      let currentQuestion = ref(0);

      return {
         questionArray, currentQuestion
      }
   },
   methods: {
      nextQuestion() {
         if (this.currentQuestion < this.questionArray.length - 1) {
            this.currentQuestion++;
         }
      },
      previousQuestion() {
         if (this.currentQuestion > 0) {
            this.currentQuestion--;
         }
      }
   },
   mounted() {
      console.log('Mounted!!')
      window.addEventListener("keyup", (event) => {
         if (event.code == 'ArrowDown') {
            this.nextQuestion();
         }
         else if (event.code == 'ArrowUp') {
            this.previousQuestion();
         }
      });
   },
   
});
</script>


<template>
   <div>
      <div id="top_bar">
         <button @click="previousQuestion">Previous Question (Up key)</button>
         <button @click="nextQuestion">Next Question (Down key)</button>
      </div>

      <div id="question_section">
         <QuestionCard 
            :question="questionArray[currentQuestion].question"
            :answer_options="questionArray[currentQuestion].options"
         ></QuestionCard>
      </div>
   </div>
</template>

I have a component called QuestionCard that displays the questions and the answer options. Just like in the App component, I have added an event listener, in order to detect key presses. Each answer option is given a key code beginning from letter A (ASCII – 65). For example, based on the answer options of the first question in questionArray above, the QuestionCard for the first question must only respond to just 3 key codes:

  • A for brown
  • B for red
  • C for black

On either

  1. pressing one of the keys assigned to an answer option button, or
  2. by clicking it,

I want to record the answer options value and pass it to a method called storeAnswer().
I have achieved goal 1 by calling this method and passing the value when a <button> is clicked. However, I’m not quite sure how to achieve goal 2.

Here’s what I have done – inside the setup() method of the QuestionCard, I have added listener to the window to detect key releases. On detection, I check if the key matches any of the assigned keys to the answer options. If so, I call the storeAnswer() method. But, I get an error saying:

Uncaught ReferenceError: storeAnswer is not defined

Here’s the code of QuestionCard.vue:

<script lang="ts">
import { defineComponent, ref } from 'vue'

export default defineComponent({
   props: {
      name: String,
      question: String,
      answer_options: Array,
   },
   methods: {
      storeAnswer(ans: any) { 
         this.selectedAns = ans;
         console.log("Button clicked: " + ans);
      }
   },
   setup(props) {
      let selectedAns = ref(null);
      
      // loop through array of answer_options and assign a key code for each one so that it can be detected
      const keyOptions: {keyCode: string, value: any}[] = [];
      for (let i=0; i < props.answer_options.length; i++) {
         keyOptions.push(
            {
               keyCode: String.fromCharCode(65+i),
               value: props.answer_options[i]
            }
         );
      }

      window.addEventListener("keyup", (event) => {
         const keyPressed = event.key.toUpperCase();

         const i = keyOptions.findIndex(Element => Element.keyCode == keyPressed);
         if (i > -1) {            
            selectedAns.value = keyOptions[i].value;
            console.log(`Option you selected is: ${keyPressed + ')' + selectedAns.value}`)
            storeAnswer();
         }
      });

      return {
         selectedAns
      }
   },
});
</script>


<template>
   <div>
      <h4>{{ question }}</h4>
      <div>
         <ul>
            <li v-for="(option, index) in answer_options" :key="index">
               <button @click="storeAnswer(option)">
                  {{  String.fromCharCode(65 + index) + ') ' + option }}
               </button>
            </li>
         </ul>
      </div>

      <!-- display the selected answer -->
      <p>
         {{ selectedAns }}
      </p>
   </div>
</template>

2

Answers


  1. Just out of the blue inside QuestionCard.vue:

    if (i > -1) {            
            selectedAns.value = keyOptions[i].value;
            console.log(`Option you selected is: ${keyPressed + ')' + selectedAns.value}`)
            this.storeAnswer();
         }
    

    You put this.storeAnswer();

    Login or Signup to reply.
  2. I’d recommend you to create a composable function. Define all your functions and state of the app like this:

     // /src/composables/useQuestions.js 
     import {ref, onMounted, computed} from 'vue'
    
     const questionArray = ref([])
     const currentQuestion = ref(0)
     const selectedAns = ref(null)
     const computed_answer_options = computed(() => {
        const questionObj = questionArray.value[currentQuestion.value]
        if (questionObj) return questionObj.options
        return []
     })
     const computed_question = computed(() => {
        const questionObj = questionArray.value[currentQuestion.value]
        if (questionObj) return questionObj.question
        return null
     })
    
     export default () => {
        onMounted(() => {
           window.addEventListener("keyup", (event) => {
              if (event.code == 'ArrowDown') {
                 nextQuestion();
              }
              else if (event.code == 'ArrowUp') {
                 previousQuestion();
              }
           });
        })
    
        // here you can call function that detect key releases and calls storeAnswer
        // I did't finish logic, but i think you got the point
    
        return {
           questionArray,
           currentQuestion,
           nextQuestion,
           previousQuestion,
           computed_answer_options,
           computed_question,
           storeAnswer
        }
     }
    
     const nextQuestion = () => {
        if (currentQuestion.value < questionArray.value.length - 1) {
           currentQuestion.value++;
        }
     }
     const previousQuestion = () => {
        if (currentQuestion.value > 0) {
           currentQuestion.value--;
        }
     }
     const storeAnswer = (ans) => {
        selectedAns.value = ans 
     }
    

    in your components use like this:

     // App.vue, QuestionCard.vue
     ...,
     setup () {
       const {
           questionArray,
           currentQuestion,
           nextQuestion,
           previousQuestion,
           computed_answer_options,
           computed_question,
           storeAnswer
        } = useQuestions()
       questionArray.value // returns []
     }
    
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