Keys In React

[Hetal Patel]

#61892

What Are Keys In React And Why Are They Important?

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[darshan.soni007]

#61893

Hello,

Keys are what help React keep track of what items have changed, been added, or been removed from a list.

Example:
render () {
return (

<li style=”list-style-type: none;”>

{this.state.todoItems.map(({task, uid}) => {

 

<li style=”list-style-type: none;”>

return
• {task}

})}

)
}

Each key must be unique among siblings. Keys make the process more efficient when dealing with lists because React can use the key on a child element to quickly know if an element is new or if it was just moved when comparing trees.

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