Get object data and target element from onClick event in react js

What about using an arrow function in the onClick handler?

handleClick = (e, data) => {
    // access to e.target here
    console.log(data);
}

<input type="checkbox" value={data.id} defaultChecked={false} onClick={((e) => this.handleClick(e, data))}/>

You can use data- element attributes and they'll be available in the target element:

import React from 'react'

export default MyComponent = () => {
  const onClick = event => {
    console.log(event.target.dataset.user)
  }

  return <div data-user="123" onClick={onClick}>Click me!</div>
}