Why is vue checkbox editing 0?

vue is a popular JavaScript framework for building user interfaces. One common component is a checkbox, which allows the user to choose between multiple options. However, sometimes, when we edit the checkbox value, it becomes 0, which is not what we expected. This article will discuss the cause of this problem and how to solve it.

First, let us take a look at the basic usage of checkboxes in vue. We can use the v-model directive to bind the value of the checkbox:

<template>
  <div>
    <input type="checkbox" v-model="checked" />
    {{ checked }}
  </div>
</template>

<script>
export default {
  data() {
    return {
      checked: false
    }
  }
}
</script>

In the above example, we bind the value of the checkbox to the checked attribute. When the checkbox is checked, the value of checked is true, otherwise it is false. We can display the checked value in the template to verify that the checkbox works the way we expect.

Now, we try to edit the value of the checkbox. For example, when the user clicks on a checkbox, we want to set its value to 1 instead of true. We can achieve it by listening to the change event of the checkbox:

<template>
  <div>
    <input type="checkbox" v-model="checked" @change="handleChange" />
    {{ checked }}
  </div>
</template>

<script>
export default {
  data() {
    return {
      checked: false
    }
  },
  methods: {
    handleChange() {
      if (this.checked) {
        this.checked = 1
      } else {
        this.checked = 0
      }
    }
  }
}
</script>

In the above code, we added a change event listener on the checkbox, when the value of the checkbox changes , the handleChange method will be called. In this method, we set the checked value to 1 or 0 respectively to achieve our needs.

However, when we run the above code, we will find that the value of the check box becomes 0 instead of 1. This is because Vue parses the checkbox value as a string, not a numeric value. Therefore, when assigning the value 1 to checked, it is parsed as the string "1", not the value 1. When the value of the checkbox is converted back to a numeric value, it becomes 0 because "1" is interpreted as a non-true value and is 0 when converted to a numeric value.

So, how should we solve this problem? One way is to use the parseInt method to convert the string to a numeric value:

<template>
  <div>
    <input type="checkbox" v-model="checked" @change="handleChange" />
    {{ checked }}
  </div>
</template>

<script>
export default {
  data() {
    return {
      checked: false
    }
  },
  methods: {
    handleChange() {
      if (this.checked) {
        this.checked = parseInt(1)
      } else {
        this.checked = parseInt(0)
      }
    }
  }
}
</script>

In the above code, we used the parseInt method to convert the numeric values ​​1 and 0 into numeric types. This way, when the checkbox's value is converted back to a numeric type, it will remain 1 instead of 0.

Another solution is to use the Number type, which can convert a string into a numeric value:

<template>
  <div>
    <input type="checkbox" v-model="checked" @change="handleChange" />
    {{ checked }}
  </div>
</template>

<script>
export default {
  data() {
    return {
      checked: false
    }
  },
  methods: {
    handleChange() {
      if (this.checked) {
        this.checked = Number(1)
      } else {
        this.checked = Number(0)
      }
    }
  }
}
</script>

In the above code, we use the Number method to convert a string into a numeric type . This way, when the checkbox's value is converted back to a numeric type, it will remain 1 instead of 0.

To summarize, when we edit the value of the checkbox in vue, we need to note that they are parsed as strings, not numeric values. To avoid this problem, you can use the parseInt or Number method to convert the string to a numeric type. In this way, we can successfully edit the value of the checkbox!

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