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Diffstat (limited to 'node_modules/stream-http/lib/capability.js')
-rw-r--r-- | node_modules/stream-http/lib/capability.js | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/node_modules/stream-http/lib/capability.js b/node_modules/stream-http/lib/capability.js new file mode 100644 index 0000000..3a17334 --- /dev/null +++ b/node_modules/stream-http/lib/capability.js @@ -0,0 +1,73 @@ +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 |