fix: Fix workaround for arrays that are passed as objects

Amends JustinBeckwith#83.

src/index.ts

@@ -134,8 +134,9 @@ function normalizeArray<T>(object?: T[]): T[] | undefined {
 
 	if (typeof object === 'object') {
 		for (const key of Object.keys(object)) {
-			if (typeof key === 'number') {
-				array[key] = object[key];
+			const num = parseInt(key);
+			if (!isNaN(num)) {
+					array[num] = object[key];
 			}
 		}
 	}

test/index.ts

@@ -80,6 +80,19 @@ describe('retry-axios', () => {
 		}
 	});
 
+	it('should support methods passed as an object', async () => {
+		const scopes = [
+			nock(url).post('/').reply(500),
+			nock(url).post('/').reply(200, 'toast'),
+		];
+		interceptorId = rax.attach();
+		const result = await axios.post(url, {}, {raxConfig: {httpMethodsToRetry: Object.assign({}, ['POST'])}});
+		assert.strictEqual(result.data, 'toast');
+		for (const s of scopes) {
+			s.done();
+		}
+	});
+
 	it('should not retry on a post', async () => {
 		const scope = nock(url).post('/').reply(500);
 		interceptorId = rax.attach();