FAQs and solutions in Vue documentation

Vue.js is a very popular front-end framework, but you will also encounter various problems when using Vue.js. This article will introduce common problems in Vue.js documents and corresponding solutions to help readers better deal with problems and improve Vue.js development efficiency.

1. Vue.js's template expression can only contain a single expression, not a statement.

This is a common syntax problem in Vue.js. The template expression of Vue.js does not support statements, only a single expression. Therefore, if you need to use conditional judgments, loops and other statements in templates, you need to use the instructions provided by Vue.js to achieve this.

For example, if you need to perform conditional judgment in the Vue.js template, you can use the v-if directive:

<template>
  <div>
    <p v-if="isShow">当isShow为真时显示该段文字</p>
  </div>
</template>

If you need to perform a loop operation, you can use the v-for directive, as shown below :

<template>
  <div>
    <ul>
      <li v-for="(key, val) in obj">{{ key }}: {{ val }}</li>
    </ul>
  </div>
</template>

2. The first letter of the component name of Vue.js must be capitalized.

The name of the component in Vue.js must start with a capital letter. This is because when Vue.js parses the template, it will parse tags starting with lowercase letters as native HTML tags, while tags starting with uppercase letters will be parsed as Vue.js components.

For example, if you define a Vue.js component named mycomponent, you need to change the tag name to 441979358effc6da8d5aa8c5b15211e6 when using it, otherwise it will be parsed as an HTML tag.

3. When using event parameters in Vue.js, it should be noted that the event processing function only receives native DOM event objects.

In Vue.js, you can use the v-on directive to bind DOM events and custom events. At the same time, data can also be passed to the event processing function through the v-bind instruction.

For example, the following code demonstrates how to use the v-on directive to bind a click event in Vue.js and pass the data to the event handler:

<template>
  <div>
    <button v-on:click="handleClick('hello')">点击我</button>
  </div>
</template>

<script>
export default {
  methods: {
    handleClick(text) {
      console.log(text)
    }
  }
}
</script>

It should be noted that, The event handling function only receives the native DOM event object and does not automatically receive the passed data. Therefore, when passing data, you need to manually pass the data as a parameter to the event handler function.

4. In Vue.js, the data attribute in the component must be a function.

The data attribute in the Vue.js component must be a function, not an object. This is because Vue.js treats each component instance as an independent data scope. If the data attribute is defined as an object, the data of multiple components will affect each other.

For example, the following code demonstrates the correct format of the Vue.js component data attribute:

<template>
  <div>
    <p>{{ text }}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      text: '我是一段文本'
    }
  }
}
</script>

5. When using the data of the parent component in Vue.js, you need to use the props attribute.

In Vue.js, it is not allowed for child components to update the data of parent components. If you need to use the data of the parent component in a child component, you should pass the data of the parent component to the child component through the props attribute.

For example, the following code demonstrates how to use the props attribute in Vue.js to pass data from a parent component to a child component:

// 父组件
<template>
  <div>
    <my-component :text="text"></my-component>
  </div>
</template>

<script>
import MyComponent from './MyComponent.vue'

export default {
  components: { MyComponent },
  data() {
    return {
      text: '我是一段文本'
    }
  }
}
</script>

// 子组件
<template>
  <div>
    <p>{{ text }}</p>
  </div>
</template>

<script>
export default {
  props: ['text']
}
</script>

6. Using the computed property in Vue.js To centrally process data calculation logic.

In Vue.js, if you need to calculate some data-related values, you can use the computed attribute to centrally handle the calculation logic. The computed attribute will automatically cache the calculation results and will only be recalculated when the relevant data changes.

For example, the following code demonstrates how to use the computed attribute to calculate the element width in Vue.js:

<template>
  <div>
    <div :style="{ width: computedWidth }">{{ text }}</div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      text: '我是一段文本'
    }
  },
  computed: {
    computedWidth() {
      return this.text.length * 10 + 'px'
    }
  }
}
</script>

The above are some common problems and corresponding solutions in the Vue.js documentation. In actual development, you may encounter more problems, which require continuous exploration and learning. I hope this article can be helpful to Vue.js developers, improve development efficiency, and better deal with various problems encountered in the project.

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