hexo/node_modules/ali-oss/shims/stream-http/lib/capability.js

73 lines
2.5 KiB
JavaScript

exports.fetch = isFunction(global.fetch) && isFunction(global.ReadableStream);
exports.writableStream = isFunction(global.WritableStream);
exports.abortController = isFunction(global.AbortController);
exports.blobConstructor = false;
try {
new Blob([new ArrayBuffer(1)]);
exports.blobConstructor = true;
} catch (e) {}
// The xhr request to example.com may violate some restrictive CSP configurations,
// so if we're running in a browser that supports `fetch`, avoid calling getXHR()
// and assume support for certain features below.
var xhr;
function getXHR() {
// Cache the xhr value
if (xhr !== undefined) return xhr;
if (global.XMLHttpRequest) {
xhr = new global.XMLHttpRequest();
// If XDomainRequest is available (ie only, where xhr might not work
// cross domain), use the page location. Otherwise use example.com
// Note: this doesn't actually make an http request.
try {
xhr.open('GET', global.XDomainRequest ? '/' : 'https://example.com');
} catch (e) {
xhr = null;
}
} else {
// Service workers don't have XHR
xhr = null;
}
return xhr;
}
function checkTypeSupport(type) {
var xhr = getXHR();
if (!xhr) return false;
try {
xhr.responseType = type;
return xhr.responseType === type;
} catch (e) {}
return false;
}
// For some strange reason, Safari 7.0 reports typeof global.ArrayBuffer === 'object'.
// Safari 7.1 appears to have fixed this bug.
var haveArrayBuffer = typeof global.ArrayBuffer !== 'undefined';
var haveSlice = haveArrayBuffer && isFunction(global.ArrayBuffer.prototype.slice);
// If fetch is supported, then arraybuffer will be supported too. Skip calling
// checkTypeSupport(), since that calls getXHR().
exports.arraybuffer = exports.fetch || (haveArrayBuffer && checkTypeSupport('arraybuffer'));
// These next two tests unavoidably show warnings in Chrome. Since fetch will always
// be used if it's available, just return false for these to avoid the warnings.
exports.msstream = !exports.fetch && haveSlice && checkTypeSupport('ms-stream');
exports.mozchunkedarraybuffer = !exports.fetch && haveArrayBuffer && checkTypeSupport('moz-chunked-arraybuffer');
// If fetch is supported, then overrideMimeType will be supported too. Skip calling
// getXHR().
exports.overrideMimeType = exports.fetch || (getXHR() ? isFunction(getXHR().overrideMimeType) : false);
exports.vbArray = isFunction(global.VBArray);
function isFunction(value) {
return typeof value === 'function';
}
xhr = null; // Help gc