Provide ability to write as text instead of as Blob #35
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…segment, not just last segment
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Currently,
write()writes everything as aBlob. On iOS and Android, cordova-plugin-file convertsBlobs toArrayBuffers, which the iOS/Android platforms then convert to base64 for transfer to the native layer. (Windows supports marshalingBlobs directly from JS to native, so that platform skips theArrayBufferand base64 conversions.)I haven't profiled Android in as much detail, but on iOS that conversion to base64 is slow and memory intensive. (Some rough timings below.) An easy workaround for text files is to skip the conversion to
Bloband write as text. That satisfies our use case of writing large JSON files.What is the intention behind using
Blobs? This PR currently comments out theBlobconversion completely. I'm assuming that breaks other use cases, so I'm open to amending the PR. For our purposes, we just need a way to opt out of theBlobconversion. An optional flag towrite()would be great. I could also imagine a CordovaPromiseFS constructor option, or maybe the behavior should be platform dependent. I figured I'd start with the simple approach before reaching out about API design.write()timings:OS: iOS 11.3
Device: iPad Model A 1489 (iPad Mini 2nd Gen)
Cordova iOS platform: 4.4.0
cordova-plugin-file version: 4.3.3
cordova-promise-fs version: 1.2.5
Test - Write a 3.0MB JSON file. Use
console.timeto measure time from callingwrite()until Promise is resolved.with
Blobconversion - 3304 ms (median of 18 runs)writing as text - 575 ms (median of 19 runs)
Let me know if I can provide more info.