A window.fetch JavaScript polyfill by GitHub.
/**
* Fetch Polyfill v3.0.0
* https://github.com/github/fetch
* (c) GitHub, Inc., MIT License
*/
var support = {
searchParams: "URLSearchParams" in self,
iterable: "Symbol" in self && "iterator" in Symbol,
blob:
"FileReader" in self &&
"Blob" in self &&
(function() {
try {
new Blob();
return true;
} catch (e) {
return false;
}
})(),
formData: "FormData" in self,
arrayBuffer: "ArrayBuffer" in self
};
function isDataView(obj) {
return obj && DataView.prototype.isPrototypeOf(obj);
}
if (support.arrayBuffer) {
var viewClasses = [
"[object Int8Array]",
"[object Uint8Array]",
"[object Uint8ClampedArray]",
"[object Int16Array]",
"[object Uint16Array]",
"[object Int32Array]",
"[object Uint32Array]",
"[object Float32Array]",
"[object Float64Array]"
];
var isArrayBufferView =
ArrayBuffer.isView ||
function(obj) {
return (
obj && viewClasses.indexOf(Object.prototype.toString.call(obj)) > -1
);
};
}
function normalizeName(name) {
if (typeof name !== "string") {
name = String(name);
}
if (/[^a-z0-9\-#$%&'*+.^_`|~]/i.test(name)) {
throw new TypeError("Invalid character in header field name");
}
return name.toLowerCase();
}
function normalizeValue(value) {
if (typeof value !== "string") {
value = String(value);
}
return value;
}
// Build a destructive iterator for the value list
function iteratorFor(items) {
var iterator = {
next: function() {
var value = items.shift();
return { done: value === undefined, value: value };
}
};
if (support.iterable) {
iterator[Symbol.iterator] = function() {
return iterator;
};
}
return iterator;
}
export function Headers(headers) {
this.map = {};
if (headers instanceof Headers) {
headers.forEach(function(value, name) {
this.append(name, value);
}, this);
} else if (Array.isArray(headers)) {
headers.forEach(function(header) {
this.append(header[0], header[1]);
}, this);
} else if (headers) {
Object.getOwnPropertyNames(headers).forEach(function(name) {
this.append(name, headers[name]);
}, this);
}
}
Headers.prototype.append = function(name, value) {
name = normalizeName(name);
value = normalizeValue(value);
var oldValue = this.map[name];
this.map[name] = oldValue ? oldValue + ", " + value : value;
};
Headers.prototype["delete"] = function(name) {
delete this.map[normalizeName(name)];
};
Headers.prototype.get = function(name) {
name = normalizeName(name);
return this.has(name) ? this.map[name] : null;
};
Headers.prototype.has = function(name) {
return this.map.hasOwnProperty(normalizeName(name));
};
Headers.prototype.set = function(name, value) {
this.map[normalizeName(name)] = normalizeValue(value);
};
Headers.prototype.forEach = function(callback, thisArg) {
for (var name in this.map) {
if (this.map.hasOwnProperty(name)) {
callback.call(thisArg, this.map[name], name, this);
}
}
};
Headers.prototype.keys = function() {
var items = [];
this.forEach(function(value, name) {
items.push(name);
});
return iteratorFor(items);
};
Headers.prototype.values = function() {
var items = [];
this.forEach(function(value) {
items.push(value);
});
return iteratorFor(items);
};
Headers.prototype.entries = function() {
var items = [];
this.forEach(function(value, name) {
items.push([name, value]);
});
return iteratorFor(items);
};
if (support.iterable) {
Headers.prototype[Symbol.iterator] = Headers.prototype.entries;
}
function consumed(body) {
if (body.bodyUsed) {
return Promise.reject(new TypeError("Already read"));
}
body.bodyUsed = true;
}
function fileReaderReady(reader) {
return new Promise(function(resolve, reject) {
reader.onload = function() {
resolve(reader.result);
};
reader.onerror = function() {
reject(reader.error);
};
});
}
function readBlobAsArrayBuffer(blob) {
var reader = new FileReader();
var promise = fileReaderReady(reader);
reader.readAsArrayBuffer(blob);
return promise;
}
function readBlobAsText(blob) {
var reader = new FileReader();
var promise = fileReaderReady(reader);
reader.readAsText(blob);
return promise;
}
function readArrayBufferAsText(buf) {
var view = new Uint8Array(buf);
var chars = new Array(view.length);
for (var i = 0; i < view.length; i++) {
chars[i] = String.fromCharCode(view[i]);
}
return chars.join("");
}
function bufferClone(buf) {
if (buf.slice) {
return buf.slice(0);
} else {
var view = new Uint8Array(buf.byteLength);
view.set(new Uint8Array(buf));
return view.buffer;
}
}
function Body() {
this.bodyUsed = false;
this._initBody = function(body) {
this._bodyInit = body;
if (!body) {
this._bodyText = "";
} else if (typeof body === "string") {
this._bodyText = body;
} else if (support.blob && Blob.prototype.isPrototypeOf(body)) {
this._bodyBlob = body;
} else if (support.formData && FormData.prototype.isPrototypeOf(body)) {
this._bodyFormData = body;
} else if (
support.searchParams &&
URLSearchParams.prototype.isPrototypeOf(body)
) {
this._bodyText = body.toString();
} else if (support.arrayBuffer && support.blob && isDataView(body)) {
this._bodyArrayBuffer = bufferClone(body.buffer);
// IE 10-11 can't handle a DataView body.
this._bodyInit = new Blob([this._bodyArrayBuffer]);
} else if (
support.arrayBuffer &&
(ArrayBuffer.prototype.isPrototypeOf(body) || isArrayBufferView(body))
) {
this._bodyArrayBuffer = bufferClone(body);
} else {
this._bodyText = body = Object.prototype.toString.call(body);
}
if (!this.headers.get("content-type")) {
if (typeof body === "string") {
this.headers.set("content-type", "text/plain;charset=UTF-8");
} else if (this._bodyBlob && this._bodyBlob.type) {
this.headers.set("content-type", this._bodyBlob.type);
} else if (
support.searchParams &&
URLSearchParams.prototype.isPrototypeOf(body)
) {
this.headers.set(
"content-type",
"application/x-www-form-urlencoded;charset=UTF-8"
);
}
}
};
if (support.blob) {
this.blob = function() {
var rejected = consumed(this);
if (rejected) {
return rejected;
}
if (this._bodyBlob) {
return Promise.resolve(this._bodyBlob);
} else if (this._bodyArrayBuffer) {
return Promise.resolve(new Blob([this._bodyArrayBuffer]));
} else if (this._bodyFormData) {
throw new Error("could not read FormData body as blob");
} else {
return Promise.resolve(new Blob([this._bodyText]));
}
};
this.arrayBuffer = function() {
if (this._bodyArrayBuffer) {
return consumed(this) || Promise.resolve(this._bodyArrayBuffer);
} else {
return this.blob().then(readBlobAsArrayBuffer);
}
};
}
this.text = function() {
var rejected = consumed(this);
if (rejected) {
return rejected;
}
if (this._bodyBlob) {
return readBlobAsText(this._bodyBlob);
} else if (this._bodyArrayBuffer) {
return Promise.resolve(readArrayBufferAsText(this._bodyArrayBuffer));
} else if (this._bodyFormData) {
throw new Error("could not read FormData body as text");
} else {
return Promise.resolve(this._bodyText);
}
};
if (support.formData) {
this.formData = function() {
return this.text().then(decode);
};
}
this.json = function() {
return this.text().then(JSON.parse);
};
return this;
}
// HTTP methods whose capitalization should be normalized
var methods = ["DELETE", "GET", "HEAD", "OPTIONS", "POST", "PUT"];
function normalizeMethod(method) {
var upcased = method.toUpperCase();
return methods.indexOf(upcased) > -1 ? upcased : method;
}
export function Request(input, options) {
options = options || {};
var body = options.body;
if (input instanceof Request) {
if (input.bodyUsed) {
throw new TypeError("Already read");
}
this.url = input.url;
this.credentials = input.credentials;
if (!options.headers) {
this.headers = new Headers(input.headers);
}
this.method = input.method;
this.mode = input.mode;
this.signal = input.signal;
if (!body && input._bodyInit != null) {
body = input._bodyInit;
input.bodyUsed = true;
}
} else {
this.url = String(input);
}
this.credentials = options.credentials || this.credentials || "same-origin";
if (options.headers || !this.headers) {
this.headers = new Headers(options.headers);
}
this.method = normalizeMethod(options.method || this.method || "GET");
this.mode = options.mode || this.mode || null;
this.signal = options.signal || this.signal;
this.referrer = null;
if ((this.method === "GET" || this.method === "HEAD") && body) {
throw new TypeError("Body not allowed for GET or HEAD requests");
}
this._initBody(body);
}
Request.prototype.clone = function() {
return new Request(this, { body: this._bodyInit });
};
function decode(body) {
var form = new FormData();
body
.trim()
.split("&")
.forEach(function(bytes) {
if (bytes) {
var split = bytes.split("=");
var name = split.shift().replace(/\+/g, " ");
var value = split.join("=").replace(/\+/g, " ");
form.append(decodeURIComponent(name), decodeURIComponent(value));
}
});
return form;
}
function parseHeaders(rawHeaders) {
var headers = new Headers();
// Replace instances of \r\n and \n followed by at least one space or horizontal tab with a space
// https://tools.ietf.org/html/rfc7230#section-3.2
var preProcessedHeaders = rawHeaders.replace(/\r?\n[\t ]+/g, " ");
preProcessedHeaders.split(/\r?\n/).forEach(function(line) {
var parts = line.split(":");
var key = parts.shift().trim();
if (key) {
var value = parts.join(":").trim();
headers.append(key, value);
}
});
return headers;
}
Body.call(Request.prototype);
export function Response(bodyInit, options) {
if (!options) {
options = {};
}
this.type = "default";
this.status = options.status === undefined ? 200 : options.status;
this.ok = this.status >= 200 && this.status < 300;
this.statusText = "statusText" in options ? options.statusText : "OK";
this.headers = new Headers(options.headers);
this.url = options.url || "";
this._initBody(bodyInit);
}
Body.call(Response.prototype);
Response.prototype.clone = function() {
return new Response(this._bodyInit, {
status: this.status,
statusText: this.statusText,
headers: new Headers(this.headers),
url: this.url
});
};
Response.error = function() {
var response = new Response(null, { status: 0, statusText: "" });
response.type = "error";
return response;
};
var redirectStatuses = [301, 302, 303, 307, 308];
Response.redirect = function(url, status) {
if (redirectStatuses.indexOf(status) === -1) {
throw new RangeError("Invalid status code");
}
return new Response(null, { status: status, headers: { location: url } });
};
export var DOMException = self.DOMException;
try {
new DOMException();
} catch (err) {
DOMException = function(message, name) {
this.message = message;
this.name = name;
var error = Error(message);
this.stack = error.stack;
};
DOMException.prototype = Object.create(Error.prototype);
DOMException.prototype.constructor = DOMException;
}
export function fetch(input, init) {
return new Promise(function(resolve, reject) {
var request = new Request(input, init);
if (request.signal && request.signal.aborted) {
return reject(new DOMException("Aborted", "AbortError"));
}
var xhr = new XMLHttpRequest();
function abortXhr() {
xhr.abort();
}
xhr.onload = function() {
var options = {
status: xhr.status,
statusText: xhr.statusText,
headers: parseHeaders(xhr.getAllResponseHeaders() || "")
};
options.url =
"responseURL" in xhr
? xhr.responseURL
: options.headers.get("X-Request-URL");
var body = "response" in xhr ? xhr.response : xhr.responseText;
resolve(new Response(body, options));
};
xhr.onerror = function() {
reject(new TypeError("Network request failed"));
};
xhr.ontimeout = function() {
reject(new TypeError("Network request failed"));
};
xhr.onabort = function() {
reject(new DOMException("Aborted", "AbortError"));
};
xhr.open(request.method, request.url, true);
if (request.credentials === "include") {
xhr.withCredentials = true;
} else if (request.credentials === "omit") {
xhr.withCredentials = false;
}
if ("responseType" in xhr && support.blob) {
xhr.responseType = "blob";
}
request.headers.forEach(function(value, name) {
xhr.setRequestHeader(name, value);
});
if (request.signal) {
request.signal.addEventListener("abort", abortXhr);
xhr.onreadystatechange = function() {
// DONE (success or failure)
if (xhr.readyState === 4) {
request.signal.removeEventListener("abort", abortXhr);
}
};
}
xhr.send(
typeof request._bodyInit === "undefined" ? null : request._bodyInit
);
});
}
fetch.polyfill = true;
if (!self.fetch) {
self.fetch = fetch;
self.Headers = Headers;
self.Request = Request;
self.Response = Response;
}