kinda working json unmarshal

cmd/main/main.go.txt

@@ -0,0 +1,108 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+
+	"github.com/xuri/excelize/v2"
+)
+
+// Initial concept from https://stackoverflow.com/q/68621039
+
+var end = errors.New("invalid end of array or object")
+
+func main() {
+	file, err := ioutil.ReadFile("test.json")
+	if err != nil {
+		panic(err)
+	}
+
+	testkey, err := objectKeys([]byte(file))
+	fmt.Println(testkey, err)
+	return
+
+	var data interface{}
+	json.Unmarshal(file, &data) // reading all json data
+	//fmt.Println(data)
+	t, ok := data.([]interface{}) // assertion Interface
+	_ = ok
+	//fmt.Printf("%[1]v  %[1]T\n", t) //map[string]interface {}
+
+	myMap := t[0] // aim here to get APP, Company and Category which will be the column name of Excel sheet
+	fmt.Printf("myMap: %v\n", myMap)
+	columnData, _ := myMap.(map[string]interface{}) // extract the underlying concrete data from interface
+	fmt.Printf("columnData: %v\n", columnData)
+	keys := make([]string, 0, len(columnData)) // creating and initializing slice to store column
+	for k := range columnData {
+		fmt.Printf("%[1]v %[1]T\n", k)
+		keys = append(keys, k)
+	}
+
+	return
+
+	xlsx := excelize.NewFile()
+	sheetName := "Sheet1"
+	xlsx.SetSheetName(xlsx.GetSheetName(1), sheetName)
+	c := 'A'
+	asciiValue := int(c)
+	var a string
+	for i := 0; i < len(keys); i++ {
+		a = string(asciiValue)
+		xlsx.SetCellValue(sheetName, a+"1", keys[i])
+		asciiValue++
+	}
+	err = xlsx.SaveAs("./Onkar.xlsx")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println("Excel file generated sucessfully")
+}
+
+func objectKeys(b []byte) ([]string, error) {
+	d := json.NewDecoder(bytes.NewReader(b))
+	t, err := d.Token()
+	if err != nil {
+		return nil, err
+	}
+	if t != json.Delim('{') {
+		return nil, errors.New("expected start of object")
+	}
+	var keys []string
+	for {
+		t, err := d.Token()
+		if err != nil {
+			return nil, err
+		}
+		if t == json.Delim('}') {
+			return keys, nil
+		}
+		keys = append(keys, t.(string))
+		if err := skipValue(d); err != nil {
+			return nil, err
+		}
+	}
+}
+func skipValue(d *json.Decoder) error {
+	t, err := d.Token()
+	if err != nil {
+		return err
+	}
+	switch t {
+	case json.Delim('['), json.Delim('{'):
+		for {
+			if err := skipValue(d); err != nil {
+				if err == end {
+					break
+				}
+				return err
+			}
+		}
+	case json.Delim(']'), json.Delim('}'):
+		return end
+	}
+	return nil
+}