format attribute selectors (#86)

closes #85

index.js

@@ -5,8 +5,11 @@ const SPACE = ' '
 const EMPTY_STRING = ''
 const COLON = ':'
 const SEMICOLON = ';'
+const QUOTE = '"'
 const OPEN_PARENTHESES = '('
 const CLOSE_PARENTHESES = ')'
+const OPEN_BRACKET = '['
+const CLOSE_BRACKET = ']'
 const TYPE_ATRULE = 'Atrule'
 const TYPE_RULE = 'Rule'
 const TYPE_BLOCK = 'Block'
@@ -210,6 +213,29 @@ export function format(css, { minify = false } = {}) {
 					}
 					break
 				}
+				case 'AttributeSelector': {
+					buffer += OPEN_BRACKET
+					buffer += child.name.name
+
+					if (child.matcher && child.value) {
+						buffer += child.matcher
+						buffer += QUOTE
+
+						if (child.value.type === 'String') {
+							buffer += child.value.value
+						} else if (child.value.type === 'Identifier') {
+							buffer += child.value.name
+						}
+						buffer += QUOTE
+					}
+
+					if (child.flags) {
+						buffer += SPACE + child.flags
+					}
+
+					buffer += CLOSE_BRACKET
+					break
+				}
 				default: {
 					buffer += substr(child)
 					break

test/selectors.test.js

@@ -137,4 +137,27 @@ test('formats multiline selectors', () => {
 	assert.is(actual, expected)
 })
 
+test('forces attribute selectors to have quoted values', () => {
+	let actual = format(`
+		[title=foo],
+		[title="bar"],
+		[title='baz'] {}
+	`)
+	let expected = `[title="foo"],
+[title="bar"],
+[title="baz"] {}`
+	assert.is(actual, expected)
+})
+
+test('adds a space before attribute selector flags', () => {
+	let actual = format(`
+		[title="foo" i],
+		[title="baz"i],
+		[title=foo i] {}
+	`)
+	let expected = `[title="foo" i],
+[title="baz" i],
+[title="foo" i] {}`
+	assert.is(actual, expected)
+})
 test.run()