React：将值从onClick传递给方法

Posted 2021-02-22

How to pass a parameter into a method from an onClick method found in the render method.

Majority of the times when you need to do this, your adding it through a loop. In this case, call a function where the item in the loop will automatically be passed into the function. This will prevent the component from re-rendering every-time it's parent changes and none of it's props or state changed.

** DO NOT DO **
Adding the code below marked with DON'T DO, will cause this component to re-render every-time it's parent changes, regardless of whether this components state or props changed.

renderUser = user => {
    return <User key={user.id} user={user} onClick={this.deleteUser} />;
  }
 
  render() {
    return (
      <div>
        <h1>Users</h1>
        <ul>
          {this.state.users.map(this.renderUser)}
        </ul>
      </div>
    );
  }
 
 
// DON'T DO
return (
  <th value={column} onClick={() => this.handleSort(column)}>{column}</th>
);