init util library

util.go

@@ -0,0 +1,47 @@
+package util
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+)
+
+// must panics if err is not nil
+func must[T any](t T, err error) T {
+	if err != nil {
+		panic(err)
+	}
+	return t
+}
+
+// attempt discards the value from a (value, err) function
+func attempt[T any](_ T, err error) error {
+	return err
+}
+
+// try discards the error from a (value, err) function
+func try[T any](t T, _ error) T {
+	return t
+}
+
+// writeJSON encodes the provided value as json and responds 200
+func writeJSON(w http.ResponseWriter, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	if err := json.NewEncoder(w).Encode(v); err != nil {
+		log.Printf("writeJSON error: %v", err)
+	}
+}
+
+// writeError logs and responds with the given formatted error message as `{"error": msg}`
+func writeError(w http.ResponseWriter, code int, msg string, args ...any) {
+	errMsg := fmt.Sprintf(msg, args...)
+	log.Println(errMsg)
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(code)
+	json.NewEncoder(w).Encode(struct {
+		Error string `json:"error"`
+	}{
+		Error: errMsg,
+	})
+}