feat: support arrays of types using anyOf (#13)

Author: theoephraim

Diff for: index.js

@@ -122,28 +122,17 @@ function convertTypes(schema) {
 	validateType(schema.type);
 
 	if (Array.isArray(schema.type)) {
-
-		if (schema.type.length > 2 || !schema.type.includes('null')) {
-			throw new Error('Type of ' + schema.type.join(',') + ' is too confusing for OpenAPI to understand. Found in ' + JSON.stringify(schema));
+		if (schema.type.includes('null')) {
+			schema.nullable = true;
 		}
-
-		switch (schema.type.length) {
-			case 0:
-				delete schema.type;
-				break;
-
-			case 1:
-				if (schema.type === 'null') {
-					schema.nullable = true;
-				}
-				else {
-					schema.type = schema.type[0];
-				}
-				break;
-
-			default:
-				schema.type = schema.type.find(type => type !== 'null');
-				schema.nullable = true;
+		const typesWithoutNull = schema.type.filter(type => type !== 'null');
+		if (typesWithoutNull.length === 0) {
+			delete schema.type
+		} else if (typesWithoutNull.length === 1) {
+			schema.type = typesWithoutNull[0];
+		} else {
+			delete schema.type;
+			schema.anyOf = typesWithoutNull.map(type => ({ type }));
 		}
 	}
 	else if (schema.type === 'null') {

Diff for: test/type-array-split.test.js

@@ -0,0 +1,65 @@
+'use strict';
+
+const convert = require('../');
+const should = require('should');
+
+it('splits type arrays correctly', async () => {
+	const schema = {
+		$schema: 'http://json-schema.org/draft-04/schema#',
+		type: 'object',
+		properties: {
+			emptyArray: {
+				type: []
+			},
+			arrayWithNull: {
+				type: ['null']
+			},
+			arrayWithSingleType: {
+				type: ['string']
+			},
+			arrayWithNullAndSingleType: {
+				type: ['null', 'string'],
+			},
+			arrayWithNullAndMultipleTypes: {
+				type: ['null', 'string', 'number'],
+			},
+			arrayWithMultipleTypes: {
+				type: ['string', 'number'],
+			},
+		}
+	};
+
+	const result = await convert(schema);
+
+	const expected = {
+		type: 'object',
+		properties: {
+			emptyArray: {},
+			arrayWithNull: {
+				nullable: true,
+			},
+			arrayWithSingleType: {
+				type: 'string',
+			},
+			arrayWithNullAndSingleType: {
+				nullable: true,
+				type: 'string',
+			},
+			arrayWithNullAndMultipleTypes: {
+				nullable: true,
+				anyOf: [
+					{ type: 'string' },
+					{ type: 'number' },
+				],
+			},
+			arrayWithMultipleTypes: {
+				anyOf: [
+					{ type: 'string' },
+					{ type: 'number' },
+				],
+			},
+		}
+	};
+
+	should(result).deepEqual(expected, 'converted');
+});