pkg/json 
An alternative JSON decoder for Go.
Features
pkg/json aims to be a drop in replacement for encoding/json.
It features:
json.Scannerwhich, when provided an external buffer, does not allocate.io.Readerfriendly; you don't need to buffer your input in memory.json.Decoder.Token()replacement that is 2-3x faster thanencoding/json.json.Decoder.NextToken()is almost allocation free.
Is it faster than fastjson/ultrajson/megajson/fujson?
Honestly, I don't know.
I have some benchmarks that show that pkg/json is faster than encoding/json for tokenisation, but this package isn't finished yet.
The Decoder.Token API is between 2-3x faster than encoding/json.Decoder.Token:
BenchmarkDecoderToken/pkgjson/canada.json.gz-16 51 21387427 ns/op 105.25 MB/s 4402975 B/op 222279 allocs/op
BenchmarkDecoderToken/encodingjson/canada.json.gz-16 18 63962471 ns/op 35.19 MB/s 17740379 B/op 889106 allocs/op
BenchmarkDecoderToken/pkgjson/citm_catalog.json.gz-16 235 5110849 ns/op 337.95 MB/s 966008 B/op 81995 allocs/op
BenchmarkDecoderToken/encodingjson/citm_catalog.json.gz-16 61 19635188 ns/op 87.96 MB/s 5665660 B/op 324799 allocs/op
BenchmarkDecoderToken/pkgjson/twitter.json.gz-16 495 2424694 ns/op 260.45 MB/s 768370 B/op 38992 allocs/op
BenchmarkDecoderToken/encodingjson/twitter.json.gz-16 98 12028296 ns/op 52.50 MB/s 3660269 B/op 187815 allocs/op
BenchmarkDecoderToken/pkgjson/code.json.gz-16 75 16111648 ns/op 120.44 MB/s 4304252 B/op 320235 allocs/op
BenchmarkDecoderToken/encodingjson/code.json.gz-16 15 75464079 ns/op 25.71 MB/s 23355964 B/op 1319125 allocs/op
BenchmarkDecoderToken/pkgjson/example.json.gz-16 23210 51699 ns/op 251.92 MB/s 16032 B/op 914 allocs/op
BenchmarkDecoderToken/encodingjson/example.json.gz-16 4767 257169 ns/op 50.64 MB/s 82416 B/op 4325 allocs/op
BenchmarkDecoderToken/pkgjson/sample.json.gz-16 1411 849803 ns/op 809.00 MB/s 213776 B/op 5081 allocs/op
BenchmarkDecoderToken/encodingjson/sample.json.gz-16 345 3550453 ns/op 193.63 MB/s 759686 B/op 26643 allocs/op
The alternative Decoder.NextToken API is between 8-10x faster than encoding/json.Decoder.Token while producing virtually no allocations:
BenchmarkDecoderNextToken/pkgjson/canada.json.gz-16 222 5157299 ns/op 436.48 MB/s 152 B/op 3 allocs/op
BenchmarkDecoderNextToken/encodingjson/canada.json.gz-16 18 67566098 ns/op 33.32 MB/s 17740510 B/op 889106 allocs/op
BenchmarkDecoderNextToken/pkgjson/citm_catalog.json.gz-16 510 2260514 ns/op 764.08 MB/s 152 B/op 3 allocs/op
BenchmarkDecoderNextToken/encodingjson/citm_catalog.json.gz-16 61 20026083 ns/op 86.25 MB/s 5665620 B/op 324799 allocs/op
BenchmarkDecoderNextToken/pkgjson/twitter.json.gz-16 1032 1093466 ns/op 577.53 MB/s 168 B/op 4 allocs/op
BenchmarkDecoderNextToken/encodingjson/twitter.json.gz-16 93 12548028 ns/op 50.33 MB/s 3660291 B/op 187815 allocs/op
BenchmarkDecoderNextToken/pkgjson/code.json.gz-16 211 5322161 ns/op 364.60 MB/s 264 B/op 6 allocs/op
BenchmarkDecoderNextToken/encodingjson/code.json.gz-16 14 78195551 ns/op 24.82 MB/s 23355961 B/op 1319125 allocs/op
BenchmarkDecoderNextToken/pkgjson/example.json.gz-16 49245 22873 ns/op 569.41 MB/s 168 B/op 4 allocs/op
BenchmarkDecoderNextToken/encodingjson/example.json.gz-16 4500 269313 ns/op 48.36 MB/s 82416 B/op 4325 allocs/op
BenchmarkDecoderNextToken/pkgjson/sample.json.gz-16 2032 553729 ns/op 1241.57 MB/s 1160 B/op 9 allocs/op
BenchmarkDecoderNextToken/encodingjson/sample.json.gz-16 332 3574484 ns/op 192.33 MB/s 759685 B/op 26643 allocs/op
Decoding into an interface{} this package is 40-50% faster than encoding/json:
BenchmarkDecoderDecodeInterfaceAny/pkgjson/canada.json.gz-16 43 27181309 ns/op 82.82 MB/s 8747225 B/op 281408 allocs/op
BenchmarkDecoderDecodeInterfaceAny/encodingjson/canada.json.gz-16 30 36930290 ns/op 60.95 MB/s 20647699 B/op 392553 allocs/op
BenchmarkDecoderDecodeInterfaceAny/pkgjson/citm_catalog.json.gz-16 156 7635508 ns/op 226.21 MB/s 5197871 B/op 89673 allocs/op
BenchmarkDecoderDecodeInterfaceAny/encodingjson/citm_catalog.json.gz-16 73 15766855 ns/op 109.55 MB/s 9410808 B/op 95496 allocs/op
BenchmarkDecoderDecodeInterfaceAny/pkgjson/twitter.json.gz-16 327 3664618 ns/op 172.33 MB/s 2130822 B/op 30182 allocs/op
BenchmarkDecoderDecodeInterfaceAny/encodingjson/twitter.json.gz-16 175 6800730 ns/op 92.86 MB/s 4359944 B/op 31775 allocs/op
BenchmarkDecoderDecodeInterfaceAny/pkgjson/code.json.gz-16 64 17302914 ns/op 112.15 MB/s 7331655 B/op 232059 allocs/op
BenchmarkDecoderDecodeInterfaceAny/encodingjson/code.json.gz-16 49 23759564 ns/op 81.67 MB/s 12332748 B/op 271292 allocs/op
BenchmarkDecoderDecodeInterfaceAny/pkgjson/example.json.gz-16 15920 76561 ns/op 170.11 MB/s 50988 B/op 739 allocs/op
BenchmarkDecoderDecodeInterfaceAny/encodingjson/example.json.gz-16 8670 139230 ns/op 93.54 MB/s 82840 B/op 782 allocs/op
BenchmarkDecoderDecodeInterfaceAny/pkgjson/sample.json.gz-16 1084 1119477 ns/op 614.12 MB/s 399983 B/op 5542 allocs/op
BenchmarkDecoderDecodeInterfaceAny/encodingjson/sample.json.gz-16 217 5418480 ns/op 126.88 MB/s 2697781 B/op 8075 allocs/op
Should I use this?
Right now? No. In the future, maybe.
I've found a bug!
Great! Please follow this two step process:
- Raise an issue
- Send a PR (unless I fix it first)
Standing on the shoulders of giants
This project is heavily influenced by Steven Schveighoffer's iopipe and Phil Pearl.