jscan
jscan provides a high-performance zero-allocation JSON iterator for Go. It's not compatible with encoding/json and doesn't provide the usual Marshal/Unmarshal capabilities, instead it focuses on fast and efficient scanning over JSON strings with on-the-fly validation.
Example
https://go.dev/play/p/v-VeiMO2fsJ
package main
import (
"fmt"
"github.com/romshark/jscan"
)
func main() {
j := `{
"s": "value",
"t": true,
"f": false,
"0": null,
"n": -9.123e3,
"o0": {},
"a0": [],
"o": {
"k": "\"v\"",
"a": [
true,
null,
"item",
-67.02e9,
["foo"]
]
},
"a3": [
0,
{
"a3.a3":8
}
]
}`
err := jscan.Scan(jscan.Options{
CachePath: true,
EscapePath: true,
}, j, func(i *jscan.Iterator) (err bool) {
fmt.Printf("| value:\n")
fmt.Printf("| level: %d\n", i.Level)
if k := i.Key(); k != "" {
fmt.Printf("| key: %q\n", i.Key())
}
fmt.Printf("| valueType: %s\n", i.ValueType)
if v := i.Value(); v != "" {
fmt.Printf("| value: %q\n", i.Value())
}
fmt.Printf("| arrayIndex: %d\n", i.ArrayIndex)
fmt.Printf("| path: '%s'\n", i.Path())
return false // No Error, resume scanning
})
if err.IsErr() {
fmt.Printf("ERR: %s\n", err)
return
}
}
Benchmark Results
The following results were recorded on an Apple M1 Max MBP running macOS 12.1
goos: darwin
goarch: arm64
Tiny JSON document ({"x":0}):
BenchmarkCalcStats/jscan/tiny-10 17281384 61.52 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter/tiny-10 12591319 93.49 ns/op 160 B/op 2 allocs/op
BenchmarkCalcStats/gofaster-jx/tiny-10 15380218 76.69 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/valyala-fastjson/tiny-10 14686556 81.48 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jscan_withpath/tiny-10 14819349 80.68 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter_withpath/tiny-10 11339800 105.5 ns/op 160 B/op 2 allocs/op
BenchmarkCalcStats/gofaster-jx_withpath/tiny-10 13993488 84.37 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/valyala-fastjson_withpath/tiny-10 11028562 107.5 ns/op 8 B/op 1 allocs/op
Small JSON document (335 bytes):
BenchmarkCalcStats/jscan/small-10 2055507 572.7 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter/small-10 1465920 818.2 ns/op 224 B/op 12 allocs/op
BenchmarkCalcStats/gofaster-jx/small-10 1301629 921.0 ns/op 16 B/op 2 allocs/op
BenchmarkCalcStats/valyala-fastjson/small-10 1667216 719.2 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jscan_withpath/small-10 1593405 747.5 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter_withpath/small-10 974680 1211 ns/op 288 B/op 21 allocs/op
BenchmarkCalcStats/gofaster-jx_withpath/small-10 909572 1296 ns/op 80 B/op 13 allocs/op
BenchmarkCalcStats/valyala-fastjson_withpath/small-10 1222809 981.1 ns/op 88 B/op 10 allocs/op
Large JSON document (26.1 MB):
BenchmarkCalcStats
BenchmarkCalcStats/jscan/large-10 30 39817379 ns/op 271 B/op 2 allocs/op
BenchmarkCalcStats/jsoniter/large-10 19 59779695 ns/op 33060224 B/op 1108611 allocs/op
BenchmarkCalcStats/gofaster-jx/large-10 22 50123860 ns/op 58 B/op 0 allocs/op
BenchmarkCalcStats/valyala-fastjson/large-10 30 40858881 ns/op 11381580 B/op 11033 allocs/op
BenchmarkCalcStats/jscan_withpath/large-10 26 44913019 ns/op 322 B/op 2 allocs/op
BenchmarkCalcStats/jsoniter_withpath/large-10 13 85893750 ns/op 55805724 B/op 1757457 allocs/op
BenchmarkCalcStats/gofaster-jx_withpath/large-10 12 95080243 ns/op 52296336 B/op 1544965 allocs/op
BenchmarkCalcStats/valyala-fastjson_withpath/large-10 21 52270306 ns/op 29394618 B/op 340766 allocs/op
Array of 1024 integers:
BenchmarkCalcStats/jscan/array_int_1024-10 49778 23505 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter/array_int_1024-10 29674 40478 ns/op 16528 B/op 1025 allocs/op
BenchmarkCalcStats/gofaster-jx/array_int_1024-10 36080 33218 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/valyala-fastjson/array_int_1024-10 46993 25360 ns/op 5 B/op 0 allocs/op
BenchmarkCalcStats/jscan_withpath/array_int_1024-10 33222 36090 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter_withpath/array_int_1024-10 13416 89293 ns/op 24496 B/op 2973 allocs/op
BenchmarkCalcStats/gofaster-jx_withpath/array_int_1024-10 14683 81523 ns/op 7970 B/op 1948 allocs/op
BenchmarkCalcStats/valyala-fastjson_withpath/array_int_1024-10 24570 48887 ns/op 8194 B/op 1024 allocs/op
Array of 1024 floating point numbers:
BenchmarkCalcStats/jscan/array_dec_1024-10 43645 25321 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter/array_dec_1024-10 27168 44132 ns/op 16528 B/op 1025 allocs/op
BenchmarkCalcStats/gofaster-jx/array_dec_1024-10 13220 90298 ns/op 6498 B/op 547 allocs/op
BenchmarkCalcStats/valyala-fastjson/array_dec_1024-10 42273 27560 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jscan_withpath/array_dec_1024-10 28917 40965 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter_withpath/array_dec_1024-10 12783 94376 ns/op 24496 B/op 2973 allocs/op
BenchmarkCalcStats/gofaster-jx_withpath/array_dec_1024-10 13364 90193 ns/op 7970 B/op 1948 allocs/op
BenchmarkCalcStats/valyala-fastjson_withpath/array_dec_1024-10 23299 50773 ns/op 8204 B/op 1024 allocs/op
Array of 1024 strings:
BenchmarkCalcStats/jscan/array_str_1024-10 36171 32719 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter/array_str_1024-10 1909 611724 ns/op 670313 B/op 1019 allocs/op
BenchmarkCalcStats/gofaster-jx/array_str_1024-10 2246 520334 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/valyala-fastjson/array_str_1024-10 15608 77085 ns/op 55 B/op 0 allocs/op
BenchmarkCalcStats/jscan_withpath/array_str_1024-10 26394 45593 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter_withpath/array_str_1024-10 1767 667022 ns/op 678284 B/op 2967 allocs/op
BenchmarkCalcStats/gofaster-jx_withpath/array_str_1024-10 1773 684708 ns/op 677621 B/op 2927 allocs/op
BenchmarkCalcStats/valyala-fastjson_withpath/array_str_1024-10 12117 98868 ns/op 8195 B/op 1024 allocs/op
Array of 1024 nullable booleans:
BenchmarkCalcStats/jscan/array_nullbool_1024-10 78883 14034 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter/array_nullbool_1024-10 44224 26998 ns/op 144 B/op 1 allocs/op
BenchmarkCalcStats/gofaster-jx/array_nullbool_1024-10 35641 33411 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/valyala-fastjson/array_nullbool_1024-10 73539 16104 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jscan_withpath/array_nullbool_1024-10 43722 27344 ns/op 0 B/op 0 allocs/op
BenchmarkCalcStats/jsoniter_withpath/array_nullbool_1024-10 15586 76804 ns/op 8112 B/op 1949 allocs/op
BenchmarkCalcStats/gofaster-jx_withpath/array_nullbool_1024-10 14474 83515 ns/op 7970 B/op 1948 allocs/op
BenchmarkCalcStats/valyala-fastjson_withpath/array_nullbool_1024-10 30286 39500 ns/op 8194 B/op 1024 allocs/op
Get by path:
BenchmarkGet/jscan-10 3957463 288.8 ns/op 16 B/op 2 allocs/op
BenchmarkGet/jsoniter-10 1272576 941.7 ns/op 496 B/op 19 allocs/op
BenchmarkGet/tidwallgjson-10 6308622 190.5 ns/op 16 B/op 2 allocs/op
BenchmarkGet/valyalafastjson-10 6188893 193.9 ns/op 0 B/op 0 allocs/op
Validation:
BenchmarkValid/tiny/jscan-10 19409760 61.44 ns/op 0 B/op 0 allocs/op
BenchmarkValid/tiny/jsoniter-10 20232646 59.52 ns/op 0 B/op 0 allocs/op
BenchmarkValid/tiny/gofaster-jx-10 15790867 75.55 ns/op 0 B/op 0 allocs/op
BenchmarkValid/tiny/encoding-json-10 27169221 43.90 ns/op 0 B/op 0 allocs/op
BenchmarkValid/tiny/tidwallgjson-10 72519966 16.46 ns/op 0 B/op 0 allocs/op
BenchmarkValid/tiny/valyala-fastjson-10 41914624 28.70 ns/op 0 B/op 0 allocs/op
BenchmarkValid/small/jscan-10 2263227 530.0 ns/op 0 B/op 0 allocs/op
BenchmarkValid/small/jsoniter-10 1482616 809.6 ns/op 56 B/op 7 allocs/op
BenchmarkValid/small/gofaster-jx-10 1414510 846.3 ns/op 16 B/op 2 allocs/op
BenchmarkValid/small/encoding-json-10 1206177 993.0 ns/op 0 B/op 0 allocs/op
BenchmarkValid/small/tidwallgjson-10 3561247 337.3 ns/op 0 B/op 0 allocs/op
BenchmarkValid/small/valyala-fastjson-10 2633577 452.2 ns/op 0 B/op 0 allocs/op
BenchmarkValid/large/jscan-10 30 39348897 ns/op 271 B/op 2 allocs/op
BenchmarkValid/large/jsoniter-10 24 47381846 ns/op 13792181 B/op 644454 allocs/op
BenchmarkValid/large/gofaster-jx-10 26 44456761 ns/op 52 B/op 0 allocs/op
BenchmarkValid/large/encoding-json-10 16 70171828 ns/op 80 B/op 0 allocs/op
BenchmarkValid/large/tidwallgjson-10 40 28859103 ns/op 2 B/op 0 allocs/op
BenchmarkValid/large/valyala-fastjson-10 40 28703367 ns/op 0 B/op 0 allocs/op
BenchmarkValid/unwind_stack/jscan-10 457160 2624 ns/op 0 B/op 0 allocs/op
BenchmarkValid/unwind_stack/jsoniter-10 15862 75624 ns/op 33145 B/op 1033 allocs/op
BenchmarkValid/unwind_stack/gofaster-jx-10 1560 763111 ns/op 131117 B/op 2048 allocs/op
BenchmarkValid/unwind_stack/encoding-json-10 212856 5536 ns/op 24 B/op 1 allocs/op
BenchmarkValid/unwind_stack/tidwallgjson-10 80488 14748 ns/op 0 B/op 0 allocs/op
BenchmarkValid/unwind_stack/valyala-fastjson-10 222 5544191 ns/op 52472494 B/op 4133 allocs/op
BenchmarkValid/array_int_1024/jscan-10 66847 17774 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_int_1024/jsoniter-10 51276 23477 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_int_1024/gofaster-jx-10 44049 26980 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_int_1024/encoding-json-10 34149 35169 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_int_1024/tidwallgjson-10 77713 15338 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_int_1024/valyala-fastjson-10 65236 18438 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_dec_1024/jscan-10 70789 15665 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_dec_1024/jsoniter-10 15679 76847 ns/op 8754 B/op 547 allocs/op
BenchmarkValid/array_dec_1024/gofaster-jx-10 14700 81322 ns/op 6498 B/op 547 allocs/op
BenchmarkValid/array_dec_1024/encoding-json-10 32197 36578 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_dec_1024/tidwallgjson-10 84492 12129 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_dec_1024/valyala-fastjson-10 51250 19518 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_nullbool_1024/jscan-10 226735 5242 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_nullbool_1024/jsoniter-10 59954 20019 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_nullbool_1024/gofaster-jx-10 44670 26863 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_nullbool_1024/encoding-json-10 56584 21165 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_nullbool_1024/tidwallgjson-10 212652 5307 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_nullbool_1024/valyala-fastjson-10 130365 9181 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_str_1024/jscan-10 35758 33207 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_str_1024/jsoniter-10 2346 509377 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_str_1024/gofaster-jx-10 2325 513011 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_str_1024/encoding-json-10 858 1392125 ns/op 1 B/op 0 allocs/op
BenchmarkValid/array_str_1024/tidwallgjson-10 2370 503992 ns/op 0 B/op 0 allocs/op
BenchmarkValid/array_str_1024/valyala-fastjson-10 4519 260450 ns/op 0 B/op 0 allocs/op
