passings array as props in reactjs

The curly braces only need to be used within JSX elements. Like this:

<MyComponent somProp={['something']} />

In the case above, the {} is the way of saying: "Evaluate the expression that I passed within and pass it as a prop". Within the {} you can pass any valid JavaScript object or expression. Note that if you pass a string, and specifically for strings, you don't need the curly braces... like <MyComponent somProp="something" />.

The above code is the equivalent of this:

var myArray = ['something'];
<MyComponent somProp={myArray} />

You actually don't need to specify PropTypes at all to use props. It's just a good way to document and verify prop types during development.

You are using the {} correctly. {} will return the value of the expression inside.

However, {['everyone']} doesn't make much sense. Here you are asking React to return the value of the array itself, rather than one of the elements/values within the array.

To get the first value out of your array, you should be doing: {this.props.config[0]} since the value "everyone" is at the 0 index of the array.

If your array had multiple values, you would do something along the lines of:

render: function() {
  var values = this.props.config.map(function(value, i){
    return (
      <p>value</p>
    );
  });

  return (
    <div className="navigation">
      helloworld {values};
    </div>
  );
}

If you truly to mean to actually print out the array itself, and not a particular value within it, you have two good options:

render: function() {
  return (
    <div className="navigation">
      helloworld {this.props.config.toString()};
    </div>
  );
}

Or

render: function() {
  return (
    <div className="navigation">
      helloworld {JSON.stringify(this.props.config)};
    </div>
  );
}