There is no syntax problem with the way you are setting state, but there could be a problem with the way you are initialising you state. You have initialized newFilm as an object state but when you set its state you are giving a string. So suppose you try to render it like {this.state.newFilm} it will throw you an error

Objects are not valid as a React child (found: object with keys {}).

as you can see in the snippet below, since the first time the component is rendered it sees an object where later its only a string.

To fix this try initializing you state newFilm as '' or take prevention when you try to render i.e. check where it contains some data and then only render.

Also I don't see someData defined in your componentDidMount function. You need to define it before you can use it.

var App = React.createClass({

  getInitialState: function() {

  return {

    list: [],

    newFilm: {},

    searchWord: '',

    searchDetails: {}

  }

},



componentDidMount: function() {

  var someData = {'name': 'abc'};

  this.setState({

    searchDetails:someData,

    newFilm: 'I am first text',

  })

},

render: function() {

  console.log(this.state.newFilm);

  return (

    <div>{this.state.newFilm}</div>

  )

}

})



ReactDOM.render(<App/>, document.getElementById('app'));

<script src=https://cdnjs.cloudflare.com/ajax/libs/react/0.14.8/react.js></script>

<script src=https://cdnjs.cloudflare.com/ajax/libs/react/0.14.8/react-dom.js></script>

<div id=app></div>