Câu hỏi phỏng vấn Reactjs
Câu hỏi

What do these three dots ( ... ) in React do?

Câu trả lời

In React, the three dots (...) represent the spread operator, which is a JavaScript expression that allows an object or array to be expanded in places where zero or more key-value pairs (for object literals) or elements (for array literals) are expected. This operator is particularly useful in React for several reasons:

  1. Passing Props: It simplifies the process of passing multiple properties to a component. For example, if you have a props object and you want to pass all of its properties to a child component, you can use the spread operator like so: <ChildComponent {...props} />. This passes all properties of the props object as props to ChildComponent[3][4].

  2. Combining Objects: When you need to combine multiple objects into one, the spread operator allows you to do this succinctly. For instance, {...obj1, ...obj2} combines all properties of obj1 and obj2 into a single new object[3][5].

  3. Array Operations: It can be used to concatenate or clone arrays without mutating the original arrays. For example, [...arr1, ...arr2] creates a new array by concatenating arr1 and arr2[4][5].

  4. Destructuring: In situations where you need to ...

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