Allow null and undefined in Stringifiable TypeScript type (#281)

Author: esetnik

index.d.ts

@@ -339,11 +339,11 @@ export interface StringifyOptions {
 	readonly skipEmptyString?: boolean;
 }
 
-export type Stringifiable = string | boolean | number;
+export type Stringifiable = string | boolean | number | null | undefined;
 
 export type StringifiableRecord = Record<
 	string,
-	Stringifiable | Stringifiable[] | null | undefined
+	Stringifiable | Stringifiable[]
 >;
 
 /**

index.test-d.ts

@@ -98,9 +98,12 @@ expectType<string>(
 	queryString.stringifyUrl({
 		url: 'https://sindresorhus.com',
 		query: {
-			fooArray: [
+			fooMixedArray: [
 				'a',
-				'b'
+				1,
+				true,
+				null,
+				undefined
 			],
 			fooNumber: 1,
 			fooBoolean: true,