promise ajax

promise.js

function ajax(method, url, data) {
  var request = new XMLHttpRequest();
  return new Promise(function (resolve, reject) {
    request.onreadystatechange = function () {
      if (request.readyState === 4) {
        if (request.status === 200) {
          resolve(request.responseText);
        } else {
          reject(reject(reject.status));
        }
      }
    };
    request.open(method, url);
    request.send(data);
  });
}
var p = ajax("GET", "https://jsonplaceholder.typicode.com/todos/1");
p.then(function (text) {
    console.log("text", text);
    return text;
  })
  .then(function (text2) {
    console.log("text2:", text2);
    return ajax("GET", "https://jsonplaceholder.typicode.com/todos/2");
  })
  .then(function (text3) {
    console.log("text3", text3);
  })
  .catch(function (status) {
    console.log(status);
  });