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