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To pass a boolean value as props to a component in React, wrap the boolean value in curly braces, e.g. Child bool={true} />All non-string type props that we pass to a component must be enclosed in curly braces.

function Child({bool}) {
  console.log(bool);

  return <div>{bool && <h2>Hello world</h2>}</div>;
}

export default function App() {
  return (
    <div>
      <Child bool={true} />
    </div>
  );
}

We pass a bool property to the component.

请注意, we have to wrap the prop in curly braces.

We may also see examples online where boolean properties are passed using only the prop name.

function Child({bool}) {
  console.log(bool);

  return <div>{bool && <h2>Hello world</h2>}</div>;
}

export default function App() {
  return (
    <div>
      <Child bool />
    </div>
  );
}

Passing a prop as is the same boolas bool={true}. However, if we pass a dynamic value (from a variable) or a false boolean value as a prop, we have to specify it explicitly like in the first code snippet.

All non-string props must be enclosed in curly braces when passed.

The curly brace syntax lets React know that there is an expression that must be evaluated.

We can then destructure and use the property in the child component bool.

The same method must be used when passing an object or array as props .

function Child({bool, obj, arr}) {
  console.log(bool);

  return (
    <div>
      <div>{bool && <h2>Hello world</h2>}</div>

      <h2>name: {obj.name}</h2>

      <h2>color: {arr[0]}</h2>
    </div>
  );
}

export default function App() {
  return (
    <div>
      <Child bool={true} obj={{id: 1, name: 'Bob'}} arr={['blue', 'green']} />
    </div>
  );
}

请注意, when we passed an object as a prop, we used two sets of curly braces.

The first group marks the start of the expression, the second is the actual object.

Strings are the only values ​​that can be passed as props without enclosing them in curly braces.

function Child({str, bool, obj, arr}) {
  console.log(bool);

  return (
    <div>
      <h2>{str}</h2>

      <div>{bool && <h2>Hello world</h2>}</div>

      <h2>name: {obj.name}</h2>

      <h2>color: {arr[0]}</h2>
    </div>
  );
}

export default function App() {
  return (
    <div>
      <Child
        str="Some content"
        bool={true}
        obj={{id: 1, name: 'Bob'}}
        arr={['blue', 'green']}
      />
    </div>
  );
}

We could also wrap the string in curly braces for consistency, but it is not required.

function Child({str, bool, obj, arr}) {
  console.log(bool);

  return (
    <div>
      <h2>{str}</h2>

      <div>{bool && <h2>Hello world</h2>}</div>

      <h2>name: {obj.name}</h2>

      <h2>color: {arr[0]}</h2>
    </div>
  );
}

export default function App() {
  return (
    <div>
      <Child
        str={'Some content'}
        bool={true}
        obj={{id: 1, name: 'Bob'}}
        arr={['blue', 'green']}
      />
    </div>
  );
}

If we use template strings or some logic to construct a string, we have to enclose it in curly braces.