chore: write readme

README.md

@@ -1,2 +1,102 @@
 # gontenttype
-Detect the format type of a given string
+1. **Detect the content type of a given string**
+   1. JSON (`application/json`)
+   2. XML (`application/xml`)
+   3. CSV (`text/csv`)
+2. **Validate syntax for a given string and supported content types**
+
+
+## Detect content type
+
+### Example
+
+#### Usage
+
+```go
+package main
+
+import (
+	"fmt"
+    "github.com/costinmrr/gontenttype"
+)
+
+func main() { 
+	// json
+	myStr := `{"foo":"bar"}`
+	contentType := gontenttype.Detect(myStr)
+	fmt.Println(contentType) // application/json
+
+	// xml
+	myStr = `<foo>bar</foo>`
+	contentType = gontenttype.Detect(myStr)
+	fmt.Println(contentType) // application/xml
+
+	// csv
+	myStr = `foo,bar`
+	contentType = gontenttype.Detect(myStr)
+	fmt.Println(contentType) // text/csv
+}
+```
+
+#### Output
+
+```shell
+application/json
+application/xml
+text/csv
+```
+
+## Validate syntax
+
+### Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/costinmrr/gontenttype/types/json"
+	"github.com/costinmrr/gontenttype/types/xml"
+	"github.com/costinmrr/gontenttype/types/csv"
+)
+
+func main() {
+	// json
+	myStr := `{"foo":"bar"}`
+	err := json.IsJSON(myStr)
+	fmt.Println(err) // nil
+
+	myStr = `{"foo":"bar"`
+	err = json.IsJSON(myStr)
+	fmt.Println(err) // unexpected end of JSON input
+
+	// xml
+	myStr = `<foo>bar</foo>`
+	err = xml.IsXML(myStr)
+	fmt.Println(err) // nil
+
+	myStr = `<foo>bar</foo`
+	err = xml.IsXML(myStr)
+	fmt.Println(err) // XML syntax error on line 1: unexpected EOF
+
+	// csv
+	myStr = `foo,bar`
+	err = csv.IsCSV(myStr)
+	fmt.Println(err) // nil
+
+	myStr = "col1,col2\nfoo,bar,baz"
+	err = csv.IsCSV(myStr)
+	fmt.Println(err) // record on line 2: wrong number of fields
+}
+```
+
+#### Output
+
+```shell
+<nil>
+unexpected end of JSON input
+<nil>
+XML syntax error on line 1: unexpected EOF
+<nil>
+record on line 2: wrong number of fields
+```

gontenttype.go

@@ -6,7 +6,7 @@ import (
 	"github.com/costinmrr/gontenttype/types/xml"
 )
 
-func GetContentType(content string) ContentType {
+func Detect(content string) ContentType {
 	err := json.IsJSON(content)
 	if err == nil {
 		return JSON

gontenttype_test.go

@@ -0,0 +1,52 @@
+package gontenttype
+
+import "testing"
+
+func TestDetect(t *testing.T) {
+	type args struct {
+		content string
+	}
+	tests := []struct {
+		name string
+		args args
+		want ContentType
+	}{
+		{
+			name: "empty",
+			args: args{content: ""},
+			want: Unsupported,
+		},
+		{
+			name: "random string defaults to csv",
+			args: args{content: "lorem ipsum dolor sit amet"},
+			want: CSV,
+		},
+		{
+			name: "random string with commas, semicolons, tabs, and pipes defaults to csv",
+			args: args{content: "foo,bar;baz\tqux|quux"},
+			want: CSV,
+		},
+		{
+			name: "csv comma separated",
+			args: args{content: "foo,bar\nbaz,qux"},
+			want: CSV,
+		},
+		{
+			name: "json",
+			args: args{content: "{\"foo\":\"bar\"}"},
+			want: JSON,
+		},
+		{
+			name: "xml",
+			args: args{content: "<foo>bar</foo>"},
+			want: XML,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Detect(tt.args.content); got != tt.want {
+				t.Errorf("Detect() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}