♻️ Add tools.WriteValue

tools/write_buffer.go

@@ -0,0 +1,44 @@
+package tools
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"time"
+)
+
+func WriteValue(buff *bytes.Buffer, val any) (n int, err error) {
+	switch v := val.(type) {
+	default:
+		err = fmt.Errorf("Unsupported type %T", v)
+	case nil:
+		return
+	case string:
+		return buff.WriteString(v)
+	case int:
+		return buff.WriteString(strconv.Itoa(v))
+	case int64:
+		return buff.WriteString(strconv.FormatInt(v, 10))
+	case float64:
+		return buff.WriteString(strconv.FormatFloat(v, 'f', -1, 64))
+	case json.Number:
+		return buff.WriteString(v.String())
+	case json.RawMessage:
+		return buff.Write(v)
+	case []byte:
+		return buff.Write(v)
+	case byte:
+		err = buff.WriteByte(v)
+		if err == nil {
+			n = 1
+		}
+	case rune:
+		return buff.WriteString(string(v))
+	case bool:
+		return buff.WriteString(strconv.FormatBool(v))
+	case time.Time:
+		return buff.WriteString(v.Format(time.RFC3339))
+	}
+	return
+}

tools/write_buffer_test.go

@@ -0,0 +1,49 @@
+package tools
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWriteBuffer(t *testing.T) {
+	when := time.Now()
+	tests := []struct {
+		name  string
+		value any
+		out   string
+		err   error
+	}{
+		{"nil", nil, "", nil},
+		{"string", "hi", "hi", nil},
+		{"bytes", []byte{104, 105}, "hi", nil},
+		{"byte", byte(104), "h", nil},
+		{"rune", 'h', "h", nil},
+		{"int", 42, "42", nil},
+		{"int64", int64(42), "42", nil},
+		{"float", 42.13, "42.13", nil},
+		{"bool", false, "false", nil},
+		{"json.Number", json.Number("42.13"), "42.13", nil},
+		{"json.RawMessage", json.RawMessage("{}"), "{}", nil},
+		{"time", when, when.Format(time.RFC3339), nil},
+		{"struct", struct{}{}, "", errors.New("Unsupported type struct {}")},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, getWriteTestRunner(tt.value, tt.out, tt.err))
+	}
+}
+
+func getWriteTestRunner(value any, out string, err error) func(*testing.T) {
+	return func(t *testing.T) {
+		buff := &bytes.Buffer{}
+		n, er := WriteValue(buff, value)
+		assert.Equal(t, len(out), n)
+		assert.Equal(t, err, er)
+		assert.Equal(t, out, buff.String())
+	}
+}