03. XMLHttpRequestのPromise化
XMLHttpRequest
function reqListener () {
console.log(this.responseText);
}
var xhr = new XMLHttpRequest();
xhr.addEventListener("load", reqListener);
xhr.open("GET", "https://swapi.co/api/people/1");
xhr.send();
XMLHttpRequestのPromise化
function get(url) {
// Return a new promise.
return new Promise(function(resolve, reject) {
// Do the usual XHR stuff
var req = new XMLHttpRequest();
req.open('GET', url);
req.onload = function() {
// This is called even on 404 etc
// so check the status
if (req.status == 200) {
// Resolve the promise with the response text
resolve(req.response);
}
else {
// Otherwise reject with the status text
// which will hopefully be a meaningful error
reject(Error(req.statusText));
}
};
// Handle network errors
req.onerror = function() {
reject(Error("Network Error"));
};
// Make the request
req.send();
});
}
get("https://swapi.co/api/people/1").then(function(response) {
console.log("Success!", response);
}, function(error) {
console.error("Failed!", error);
})
