React takes in a object name, to which you have given the name : a

If you have studied Objects in JavaScript, then to fetch the data, we use 'MyObj'.'key' to fetch the data, here is an example:

const user = { first_name = 'Ayaan', last_name = 'Abbasi } so, to fetch your first name, we do the following: document.write(user.first_name)

hence, in your example, your variable name is a and your data is the title, hence, to fetch your title, you can do a.title ,

for further information on components and props, please read this

The general name for it "props" (in your component it is "a").

"Props" is an object that has all the properties passed to the component.

For example;

<ExampleComponent isEnabled={true} isClickable={false} />

Then you can access those properties in your component in two ways;

1: Get the prop variable and use it an object as you do in your example. 2: Destruct the object in your component to use as you want.

const ExampleComponent = ({isEnabled, isClickable}) => {
    return "<></>";
});

For more information:

https://reactjs.org/docs/components-and-props.html

you passed a prop in your component.

import HelloMessage from "./HelloMessage";
export default function App() {
  return (
    <div className="App">
      <HelloMessage name={"tomnyson"} />
    </div>
  );
}

export default function HelloMessage({name}) {
  return (
    <h1>{name}</h1>
  )
}

link source: https://codesandbox.io/s/hopeful-tesla-3uk94?file=/src/App.js look this document

https://reactjs.org/docs/components-and-props.html