validateFields function added

src/middlewares/utils/validateFields.ts

+import { Request } from "express";
+import { ValidationError } from "./ValidationError";
+
+interface IValidateFields {
+  fields: {
+    name: string;
+    required: boolean;
+  }[];
+  reqBody: Request["body"];
+}
+
+export function validateFields({ fields, reqBody }: IValidateFields) {
+  fields.forEach((field) => {
+    const value = reqBody[field.name];
+    if (field.required && !value) {
+      throw new ValidationError(400, `Field: {${field.name}} is required!`);
+    }
+  });
+}