what is promises in reactjs

1componentWillMount() {
2 var promise = new Promise( (resolve, reject) => {
3
4  let name = 'Paul'
5
6  if (name === 'Paul') {
7   resolve("Promise resolved successfully");
8  }
9  else {
10   reject(Error("Promise rejected"));
11  }
12 });
13
14 let obj = {newName: ''};
15
16 promise.then( result => {
17  this.setState({name: result});
18 }, function(error) {
19  this.setState({name: error});
20 });
21}

1componentWillMount() {
2 var promise = new Promise( (resolve, reject) => {
3
4  let name = 'Paul'
5
6  if (name === 'Paul') {
7   resolve("Promise resolved successfully");
8  }
9  else {
10   reject(Error("Promise rejected"));
11  }
12 });
13
14 let obj = {newName: ''};
15
16 promise.then( result => {
17  this.setState({name: result});
18 }, function(error) {
19  this.setState({name: error});
20 });
21}
22