Read JSON File form a filePath. American movies dataset can be found here: https://raw.githubusercontent.com/prust/wikipedia-movie-data/master/movies.json. 200,000+ Jeopardy question dataset can be found here: https://www.reddit.com/r/datasets/comments/1uyd0t/200000_jeopardy_questions_in_a_json_file/.

json_read.go

package main

import (
	"encoding/json"
	"io/ioutil"
)

func readJSON(fileName string, filter func(map[string]interface{}) bool) []map[string]interface{} {
	datas := []map[string]interface{}{}

	file, _ := ioutil.ReadFile(fileName)
	json.Unmarshal(file, &datas)

	filteredData := []map[string]interface{}{}

	for _, data := range datas {
		// Do some filtering
		if filter(data) {
			filteredData = append(filteredData, data)
		}
	}

	return filteredData
}

json_read_token.go

package main

import (
	"encoding/json"
	"os"
)

func readJSONToken(fileName string, filter func(map[string]interface{}) bool) []map[string]interface{} {
	file, _ := os.Open(fileName)
	defer file.Close()

	decoder := json.NewDecoder(file)

	filteredData := []map[string]interface{}{}

	// Read the array open bracket
	decoder.Token()

	data := map[string]interface{}{}
	for decoder.More() {
		decoder.Decode(&data)

		if filter(data) {
			filteredData = append(filteredData, data)
		}
	}

	return filteredData
}

read_test.go

package main

import (
	"testing"
)

func BenchmarkMovieRead(b *testing.B) {
	readJSON("movie.json", func(data map[string]interface{}) bool {
		return data["year"].(float64) >= 2010
	})
}

func BenchmarkMovieReadToken(b *testing.B) {
	readJSONToken("movie.json", func(data map[string]interface{}) bool {
		return data["year"].(float64) >= 2010
	})
}

func BenchmarkQRead(b *testing.B) {
	readJSON("question.json", func(data map[string]interface{}) bool {
		return data["show_number"].(string) == "4680"
	})
}

func BenchmarkQReadToken(b *testing.B) {
	readJSONToken("question.json", func(data map[string]interface{}) bool {
		return data["show_number"].(string) == "4680"
	})
}

write_test.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
	"testing"
	"time"
)

func makeData(n int) interface{} {
	datas := []map[string]interface{}{}
	for i := 0; i < n; i++ {
		data := map[string]interface{}{
			"Name":        fmt.Sprintf("Person %v", i),
			"Address":     "Somewhere we don't really know",
			"Description": "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.",
			"Age":         i + 10,
			"PhoneNumber": i + 99,
			"CreatedOn":   time.Now(),
		}
		datas = append(datas, data)
	}

	return datas
}

func BenchmarkMarshalWriteBig(b *testing.B) {
	for n := 0; n < b.N; n++ {
		jsonString, _ := json.Marshal(makeData(1000000))
		ioutil.WriteFile("big_marhsall.json", jsonString, os.ModePerm)
	}
}

func BenchmarkEncodeWriteBig(b *testing.B) {
	for n := 0; n < b.N; n++ {
		file, _ := os.OpenFile("big_encode.json", os.O_CREATE, os.ModePerm)
		defer file.Close()

		encoder := json.NewEncoder(file)
		encoder.Encode(makeData(1000000))
	}
}

func BenchmarkMarshalWrite(b *testing.B) {
	for n := 0; n < b.N; n++ {
		jsonString, _ := json.Marshal(makeData(10000))
		ioutil.WriteFile("small_marhsall.json", jsonString, os.ModePerm)
	}
}

func BenchmarkEncodeWrite(b *testing.B) {
	for n := 0; n < b.N; n++ {
		file, _ := os.OpenFile("small_encode.json", os.O_CREATE, os.ModePerm)
		defer file.Close()

		encoder := json.NewEncoder(file)
		encoder.Encode(makeData(10000))
	}
}