FIX: Decode brack-seperator value before splitting it with seperator

The original implementation was splitting the received value before it
then decoded the value. Because the value was URL encoded, the split
function could not find the seperator to successfully split. Adjusted
the order of operations which fixes #388

base.js

@@ -221,7 +221,7 @@ function parserForArrayFormat(options) {
 
 				const arrayValue = value === null
 					? []
-					: value.split(options.arrayFormatSeparator).map(item => decode(item, options));
+					: decode(value, options).split(options.arrayFormatSeparator)
 
 				if (accumulator[key] === undefined) {
 					accumulator[key] = arrayValue;

test/parse.js

@@ -215,6 +215,16 @@ test('query strings having a brackets+separator array and format option as `brac
 	}), {foo: ['']});
 });
 
+test('query strings having a brackets+separator array and format option as `bracket-separator` with a URL encoded value', t => {
+	t.deepEqual(queryString.parse('?testA%5B%5D=1&testB%5B%5D=a%2Cb%2Cc%2Cd%2Ce%2Cf&testC=true', {
+		arrayFormat: 'bracket-separator',
+	}), {
+		testA: ['1'],
+      	testB: ['a', 'b', 'c', 'd', 'e', 'f'],
+      	testC: 'true',
+	});
+});
+
 test('query strings having = within parameters (i.e. GraphQL IDs)', t => {
 	t.deepEqual(queryString.parse('foo=bar=&foo=ba=z='), {foo: ['bar=', 'ba=z=']});
 });