The principle of key in vue

The key in Vue is an attribute used to uniquely identify a list item. It is crucial for efficient rendering and data management. By comparing changes on the virtual DOM, Vue can use keys to identify list items and avoid unnecessary DOM re-rendering, thereby optimizing performance and ensuring unique identification of list items.

The principle of key in Vue

Question: What is the function of key in Vue ?

Answer: The key in Vue is an attribute used to uniquely identify a list item. It is crucial for efficient rendering and data management of Vue.

Principle:

Vue uses virtual DOM (Virtual Document Object Model) to optimize rendering performance. The virtual DOM saves an in-memory copy of the real DOM. Vue compares the changes on the virtual DOM with the changes on the real DOM, and only updates the changed parts.

When the list items are updated (such as order change, addition or deletion), Vue uses key to identify each list item, thereby avoiding unnecessary DOM re-rendering.

Benefits:

• Efficient rendering: Vue can use key to skip re-rendering of unchanged list items, thus improving performance.
• Unique identification: key ensures that list items remain uniquely identified when updated, even if their contents are the same.
• Tracking status: Vue can use key to track the status of a list item, such as its creation or destruction time.

Usage Notes:

• Must be unique: Each item in the list must have a unique key.
• No modification: During the life cycle of the list item, its key should not change.
• Used in v-for: key must be used in the v-for directive.
• Use simple values: For best performance, it is recommended to use simple values ​​as keys, such as IDs, numbers, or strings.

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