Steps for initializing a Vue component instance by passing parameters

Question

Steps for initializing a Vue component instance by passing parameters

Being a novice in the realm of Vue, I am eager to gain knowledge on how to effectively create and reuse Vue components. However, I am encountering an issue where the initial data passed to a component does not update upon a click event. Shown below is a snippet of my code (full version available at https://jsfiddle.net/gpawel/486ysvxj/33/). Could you please point out what might be causing this problem? Thank you.

<div id="components-demo">
  <button-counter count='3'></button-counter>
  <br><br>
  <button-counter count='4'></button-counter>
</div>

Vue.component('button-counter', {
    props: ['count'],
    methods: {
    add: function() {
        return {count: count++}
    }
  },
  template: '<button v-on:click="add()">You clicked me {{count}}  times.</button>'
})

new Vue({ 
    el: '#components-demo'
})

javascript vue.js

Answer 1

Answer №1

Check out the live demo here: https://jsfiddle.net/68p1u9ks/

Vue.component('button-counter', {
    props: ['initialCount'],
    data: function () {
        return {
          count: 0,
        }
    },
    methods: {
        add: function() {
            this.count++
        },
    },
    created() {
          this.count = this.initialCount
    },
    template: '<button v-on:click="add()">You clicked me {{count}} times.</button>'
})

In my opinion, it is important to keep track of the state within the button-counter component. Additionally, consider renaming the count prop to initial-count.

<div id="components-demo">
  <button-counter :initial-count='3'></button-counter>
  <br><br>
  <button-counter :initial-count='4'></button-counter>
</div>

Answer 2

Check out the live demo here: https://jsfiddle.net/68p1u9ks/

Vue.component('button-counter', {
    props: ['initialCount'],
    data: function () {
        return {
          count: 0,
        }
    },
    methods: {
        add: function() {
            this.count++
        },
    },
    created() {
          this.count = this.initialCount
    },
    template: '<button v-on:click="add()">You clicked me {{count}} times.</button>'
})

In my opinion, it is important to keep track of the state within the button-counter component. Additionally, consider renaming the count prop to initial-count.

<div id="components-demo">
  <button-counter :initial-count='3'></button-counter>
  <br><br>
  <button-counter :initial-count='4'></button-counter>
</div>

Answer 3

Answer №2

Check out the updated JSFiddle for your reference. Avoid directly changing the count property, instead store it as a data first and then update the internalCount. Also, make sure to use a colon (:) when casting the prop to a Number rather than a string.

props: ['count'],
  data() {
  return {
    internalCount: this.count
  }
},
methods: {
  add: function() {
    return {
      count: this.internalCount++
    }
  }
},

Answer 4

Check out the updated JSFiddle for your reference. Avoid directly changing the count property, instead store it as a data first and then update the internalCount. Also, make sure to use a colon (:) when casting the prop to a Number rather than a string.

props: ['count'],
  data() {
  return {
    internalCount: this.count
  }
},
methods: {
  add: function() {
    return {
      count: this.internalCount++
    }
  }
},

Answer 5

Answer №3

Updating props in a child component is not possible directly. To modify props, you can utilize the $emit method:

Example of parent component:

<template>
<div>
  <child :count="count" @add="add" />
</div>
</template>
<script>
export default {
  data() {
    return {
      count: 1
    };
  },
  methods: {
   add() {
     this.count += 1;
   }  
  }
}
</script>

Example of child component:

<template>
  <button v-on:click="add()">You clicked me {{inComponentCount}} times.</button>
</template>
<script>
export default {
  props: [count],
  computed: {
    inComponentCount() {
      return this.count;
    }
  },
  methods: {
   add() {
     this.$emit('add')
   }  
  }
}
</script>

Answer 6

Updating props in a child component is not possible directly. To modify props, you can utilize the $emit method:

Example of parent component:

<template>
<div>
  <child :count="count" @add="add" />
</div>
</template>
<script>
export default {
  data() {
    return {
      count: 1
    };
  },
  methods: {
   add() {
     this.count += 1;
   }  
  }
}
</script>

Example of child component:

<template>
  <button v-on:click="add()">You clicked me {{inComponentCount}} times.</button>
</template>
<script>
export default {
  props: [count],
  computed: {
    inComponentCount() {
      return this.count;
    }
  },
  methods: {
   add() {
     this.$emit('add')
   }  
  }
}
</script>

Steps for initializing a Vue component instance by passing parameters

Answer №1

Answer №2

Answer №3

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