Add fast-bail path for string comparison (#405)

src/string-utils.js

@@ -26,9 +26,12 @@ function compareChar(referenceCode, testCode) {
  * @returns {boolean} true if the two strings are the same, false otherwise
  */
 export function strEquals(base, maybe) {
+  if (base === maybe) return true
+
   let len = base.length;
   if (len !== maybe.length) return false
 
+
   for (let i = 0; i < len; i++) {
     if (compareChar(base.charCodeAt(i), maybe.charCodeAt(i)) === false) {
       return false
@@ -50,6 +53,8 @@ export function strEquals(base, maybe) {
  * @returns {boolean} true if `test` ends with `base`, false otherwise
  */
 export function endsWith(base, maybe) {
+  if (base === maybe) return true
+
   let len = maybe.length
   let offset = len - base.length
 
@@ -79,6 +84,8 @@ export function endsWith(base, maybe) {
  * @returns {boolean} true if `base` starts with `maybe`, false otherwise
  */
 export function startsWith(base, maybe) {
+  if (base === maybe) return true
+
   let len = base.length
   if (maybe.length < len) return false
 

src/string-utils.test.js

@@ -19,6 +19,7 @@ StringUtils('endsWith', () => {
   assert.ok(endsWith('keyframes', '-webkit-keyframes'))
   assert.ok(endsWith('keyframes', 'testkeyframes'))
   assert.ok(endsWith('keyframes', 'testKeyframes'))
+  assert.ok(endsWith('test', 'test'))
 
   assert.not.ok(endsWith('keyframes', ''))
   assert.not.ok(endsWith('keyframes', 'test'))
@@ -30,6 +31,7 @@ StringUtils('startsWith', () => {
   assert.ok(startsWith('animation', 'animation'))
   assert.ok(startsWith('animation', 'animation-duration'))
   assert.ok(startsWith('animation', 'Animation'))
+  assert.ok(startsWith('test', 'test'))
 
   assert.not.ok(startsWith('data:', 'nope'))
   assert.not.ok(startsWith('test', ''))