Usage rules of v-if in vue

The v-if directive in Vue.js displays or hides elements based on Boolean expressions. The syntax is <div v-if="condition"></div>, but it does not remove event listeners. controllers and bindings. Compared to v-show, v-if deletes and recreates elements (potentially incurring a performance penalty), while v-show only modifies the display attribute (less performance overhead). For frequent condition switching, use v-show; for complex conditions, delayed rendering, or scenes that require immediate rendering of elements, use v-if.

Usage rules of v-if in Vue

Use of v-if directive

v-if is an important directive in Vue.js, used to show or hide elements based on conditions. When the condition is true, the v-if element will be rendered; otherwise, it will be removed from the DOM.

Syntax

The syntax of the v-if instruction is:

<div v-if="condition"></div>

Among them:

• condition is a Boolean expression used to determine whether to display the element.

Note:

• v-if can only be used for a single element, not a group of elements.
• v-if does not remove event listeners and bindings, so they will still be in effect when the element is displayed again.

Differences from v-show

v-if and v-show are both instructions for conditionally rendering elements, but how they work Different from:

• v-if: Deletes and recreates elements, which may result in performance loss, especially in frequent condition switches.
• v-show: Modify only the element's display attribute, thereby hiding or showing the element. It does not recreate elements, so there is less performance overhead.

Best Practices

When choosing between using v-if or v-show, please follow the following best practices:

• Frequent conditional switching: Use v-show as it does not recreate elements.
• Complex conditions: Use v-if as it supports more complex conditions.
• Delayed Rendering: If you want to delay rendering of an element under certain conditions, use v-if as it will render the element as soon as the condition is met.

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