Simple ordered map for Go, with JSON restrictions. The main purpose is to keep same order of keys after parsing JSON and generating it again, so Unmarshal followed by Marshal generates exactly the same JSON structure
Keys are strings, Values are any JSON values (number, string, boolean, null, array, map/object)
Storage is O(n), operations are O(1), except for optional operations in slow.go file
When Unmarshalling, any nested map from JSON is created as ordered jsonmap, including maps in nested arrays
Inspired by wk8/go-ordered-map and iancoleman/orderedmap
Similar to Go native map, jsonmap has O(1) time for Get, Set, Delete. Additionally it has Push, First, Last, Next, Prev operations, which are also O(1). Suite benchmark does 10k of Set and Get, and 1k of Delete operations. jsonmap performance is on par with native Go map
➜ go test -bench . -benchmem ./test goos: darwin goarch: arm64 pkg: github.com/metalim/jsonmap/test Benchmark/Suite/jsonmap-10 36 31614692 ns/op 17046302 B/op 623006 allocs/op Benchmark/Suite/gomap-10 48 25116164 ns/op 14791564 B/op 522925 allocs/op Benchmark/Ops/Get/jsonmap-10 11191284 112.3 ns/op 0 B/op 0 allocs/op Benchmark/Ops/Get/gomap-10 11543529 97.88 ns/op 0 B/op 0 allocs/op Benchmark/Ops/SetExisting/jsonmap-10 5847512 291.3 ns/op 106 B/op 1 allocs/op Benchmark/Ops/SetExisting/gomap-10 7608140 174.6 ns/op 89 B/op 1 allocs/op Benchmark/Ops/SetNew/jsonmap-10 2548009 429.3 ns/op 242 B/op 2 allocs/op Benchmark/Ops/SetNew/gomap-10 5143821 212.3 ns/op 133 B/op 1 allocs/op Benchmark/Ops/Delete/jsonmap-10 7642382 156.0 ns/op 0 B/op 0 allocs/op Benchmark/Ops/Delete/gomap-10 10592187 102.4 ns/op 0 B/op 0 allocs/op PASS ok github.com/metalim/jsonmap/test 143.577s $ go get github.com/metalim/jsonmappackage main import ( "encoding/json" "fmt" "github.com/metalim/jsonmap" ) const sampleJSON = `{"an":"article","empty":null,"sub":{"s":1,"e":2,"x":3,"y":4},"bool":false,"array":[1,2,3]}` func main() { m := jsonmap.New() // unmarshal, keeping order err := json.Unmarshal([]byte(sampleJSON), &m) if err != nil { panic(err) } // get values val, ok := m.Get("an") fmt.Println("an: ", val, ok) // article true val, ok = m.Get("non-existant") fmt.Println("non-existant", val, ok) // <nil> false // marshal, keeping order output, err := json.Marshal(&m) if err != nil { panic(err) } if string(output) == sampleJSON { fmt.Println("output == sampleJSON") } // iterate fmt.Println("forward order:") for el := m.First(); el != nil; el = el.Next() { fmt.Printf("\t%s: %v\n", el.Key(), el.Value()) } fmt.Println() fmt.Println("backwards order:") for el := m.Last(); el != nil; el = el.Prev() { fmt.Printf("\t%s: %v\n", el.Key(), el.Value()) } fmt.Println() fmt.Println(`forward from key "sub":`) for el := m.GetElement("sub"); el != nil; el = el.Next() { fmt.Printf("\t%s: %v\n", el.Key(), el.Value()) } fmt.Println() // print map fmt.Println(m) // map[an:article empty:<nil> sub:map[s:1 e:2 x:3 y:4] bool:false array:[1 2 3]] // set new values, keeping order of existing keys m.Set("an", "bar") m.Set("truth", true) fmt.Println(m) // map[an:bar empty:<nil> sub:map[s:1 e:2 x:3 y:4] bool:false array:[1 2 3] truth:true] // delete key "sub" m.Delete("sub") fmt.Println(m) // map[an:bar empty:<nil> bool:false array:[1 2 3] truth:true] // update value for key "an", and move it to the end m.Push("an", "end") fmt.Println(m) // map[empty:<nil> bool:false array:[1 2 3] truth:true an:end] data, err := json.Marshal(&m) if err != nil { panic(err) } fmt.Println(string(data)) // {"empty":null,"bool":false,"array":[1,2,3],"truth":true,"an":"end"} }- iancoleman/orderedmap — has O(n) time for Delete
- wk8/go-ordered-map — Unmarshal creates nested maps as native unordered maps, which makes it useless for my purposes
Let me know of other alternatives, I'll add them here