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/** * Create a blob builder even when vendor prefixes exist */
var BlobBuilder = global.BlobBuilder || global.WebKitBlobBuilder || global.MSBlobBuilder || global.MozBlobBuilder;
/** * Check if Blob constructor is supported */
var blobSupported = (function() { try { var a = new Blob(['hi']); return a.size === 2; } catch(e) { return false; } })();
/** * Check if Blob constructor supports ArrayBufferViews * Fails in Safari 6, so we need to map to ArrayBuffers there. */
var blobSupportsArrayBufferView = blobSupported && (function() { try { var b = new Blob([new Uint8Array([1,2])]); return b.size === 2; } catch(e) { return false; } })();
/** * Check if BlobBuilder is supported */
var blobBuilderSupported = BlobBuilder && BlobBuilder.prototype.append && BlobBuilder.prototype.getBlob;
/** * Helper function that maps ArrayBufferViews to ArrayBuffers * Used by BlobBuilder constructor and old browsers that didn't * support it in the Blob constructor. */
function mapArrayBufferViews(ary) { for (var i = 0; i < ary.length; i++) { var chunk = ary[i]; if (chunk.buffer instanceof ArrayBuffer) { var buf = chunk.buffer;
// if this is a subarray, make a copy so we only
// include the subarray region from the underlying buffer
if (chunk.byteLength !== buf.byteLength) { var copy = new Uint8Array(chunk.byteLength); copy.set(new Uint8Array(buf, chunk.byteOffset, chunk.byteLength)); buf = copy.buffer; }
ary[i] = buf; } } }
function BlobBuilderConstructor(ary, options) { options = options || {};
var bb = new BlobBuilder(); mapArrayBufferViews(ary);
for (var i = 0; i < ary.length; i++) { bb.append(ary[i]); }
return (options.type) ? bb.getBlob(options.type) : bb.getBlob(); };
function BlobConstructor(ary, options) { mapArrayBufferViews(ary); return new Blob(ary, options || {}); };
module.exports = (function() { if (blobSupported) { return blobSupportsArrayBufferView ? global.Blob : BlobConstructor; } else if (blobBuilderSupported) { return BlobBuilderConstructor; } else { return undefined; } })();
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