2.0.0

Я пока перечислю - умру.
Надо научиться писать changelog постепенно.

src/utility/class-validators/conditional-field.ts

@@ -0,0 +1,39 @@
+import {
+	registerDecorator,
+	ValidationArguments,
+	ValidationOptions,
+} from "class-validator";
+
+// noinspection FunctionNamingConventionJS
+export function NullIf(
+	canBeNull: (cls: object) => boolean,
+	validationOptions?: ValidationOptions,
+) {
+	return function (object: object, propertyName: string) {
+		registerDecorator({
+			name: "nullIf",
+			target: object.constructor,
+			propertyName: propertyName,
+			options: validationOptions,
+			constraints: [canBeNull],
+			validator: {
+				validate(value: any, args: ValidationArguments) {
+					const canBeNullFunc: (cls: object) => boolean =
+						args.constraints[0];
+
+					const canBeNull = canBeNullFunc(args.object);
+					const currentValue = value;
+
+					// Логика валидации: если одно из полей null, то другое тоже должно быть null
+
+					return canBeNull
+						? currentValue !== null
+						: currentValue === null;
+				},
+				defaultMessage(args: ValidationArguments) {
+					return `${args.property} must be ${args.property === null ? "non-null" : "null"}!`;
+				},
+			},
+		});
+	};
+}