计算属性已分配给但没有设置器 - 切换组件

问题描述

我正在 Vue 中创建一个简单的开关切换组件，它有一个 v-model 和 @updated.但是当用户切换开关时，我似乎无法更改模型.首先，我收到错误以避免直接改变道具.但现在我又遇到了另一个错误.

I am creating a simple switch toggle component in Vue where it has a v-model and @updated. But I can't seem to change the model when the user toggles the switch. First I was getting the error to avoid mutating a prop directly. But now I am getting another error.

[Vue 警告]:计算属性isSwitchOn"已分配给但它有没有二传手.

组件应该这样使用

<iswitch v-model="switchGender" @updated="handleUpdatedGender" />

这是组件本身

export default {
    template: `
        <span
            @click="toggleSwitch"
            :class="{ active: isSwitchOn }">

            <span class="toggle-knob"></span>
        </span>
    `,

    props: ['value'],

    methods:
    {
        toggleSwitch()
        {
            this.isSwitchOn = !this.isSwitchOn

            this.$emit('input', this.isSwitchOn)
            this.$emit('updated')
        }
    },

    computed:
    {
        isSwitchOn()
        {
            return this.value
        }
    },
};

推荐答案

错误是由这个语句触发的:this.isSwitchOn = !this.isSwitchOn.您正在尝试为计算属性赋值，但您没有提供 setter.

The error is triggered by this statement: this.isSwitchOn = !this.isSwitchOn. You are trying to assign a value to a computed property but you didn't provide a setter.

您需要如下定义您的计算属性，使其作为 getter 和 setter 工作:

You need to define your computed property as follow for it to work as a getter and a setter:

computed:
{
    isSwitchOn:
    {
        get()
        {
            return this.value
        },
        set(value)
        {
            this.value = value
        }
    }
}

另外，不建议直接修改 prop.您可以做的是添加一个新的数据属性并使用观察者将其与 value 道具同步.

Also, it is not advised to mutate a prop directly. What you could do is to add a new data property and sync it with the value prop using a watcher.

我认为这样的事情会奏效:

I think something like this will work:

props: ['value'],
data()
{
    return {
       val: null
    }
},
computed:
{
    isSwitchOn:
    {
        get()
        {
            return this.val
        },
        set(value)
        {
            this.val = value
        }
    }
},
watch: {
   value(newVal) {
       this.val = newVal
   }
}

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