Don't confuse modules with similar names (#9)

* Don't confuse modules with similar names

* More bugfixes for similar module names

* Even more improvements for similar module names

Author: szwacz

src/index.js

@@ -3,7 +3,17 @@ import fs from 'fs';
 
 // Helper functions
 const noop = () => null;
-const startsWith = (needle, haystack) => ! haystack.indexOf(needle);
+const matches = (key, importee) => {
+  if (importee.length < key.length) {
+    return false;
+  }
+  if (importee === key) {
+    return true;
+  }
+  const importeeStartsWithKey = (importee.indexOf(key) === 0);
+  const importeeHasSlashAfterKey = (importee.substring(key.length)[0] === '/');
+  return importeeStartsWithKey && importeeHasSlashAfterKey;
+};
 const endsWith = (needle, haystack) => haystack.slice(-needle.length) === needle;
 const isFilePath = id => /^\.?\//.test(id);
 const exists = uri => {
@@ -30,7 +40,7 @@ export default function alias(options = {}) {
   return {
     resolveId(importee, importer) {
       // First match is supposed to be the correct one
-      const toReplace = aliasKeys.find(key => startsWith(key, importee));
+      const toReplace = aliasKeys.find(key => matches(key, importee));
 
       if (!toReplace) {
         return null;

test/index.js

@@ -19,22 +19,38 @@ test(t => {
   t.is(typeof result.resolveId, 'function');
 });
 
-// Simple aliasing
-test(t => {
+test('Simple aliasing', t => {
   const result = alias({
     foo: 'bar',
     pony: 'paradise',
+    './local': 'global',
   });
 
   const resolved = result.resolveId('foo', '/src/importer.js');
   const resolved2 = result.resolveId('pony', '/src/importer.js');
+  const resolved3 = result.resolveId('./local', '/src/importer.js');
 
   t.is(resolved, 'bar');
   t.is(resolved2, 'paradise');
+  t.is(resolved3, 'global');
 });
 
-// Local aliasing
-test(t => {
+test('Will not confuse modules with similar names', t => {
+  const result = alias({
+    foo: 'bar',
+    './foo': 'bar',
+  });
+
+  const resolved = result.resolveId('foo2', '/src/importer.js');
+  const resolved2 = result.resolveId('./fooze/bar', '/src/importer.js');
+  const resolved3 = result.resolveId('./someFile.foo', '/src/importer.js');
+
+  t.is(resolved, null);
+  t.is(resolved2, null);
+  t.is(resolved3, null);
+});
+
+test('Local aliasing', t => {
   const result = alias({
     foo: './bar',
     pony: './par/a/di/se',
@@ -51,8 +67,7 @@ test(t => {
   t.is(resolved4, '/src/highly/nested/par/a/di/se.js');
 });
 
-// Absolute local aliasing
-test(t => {
+test('Absolute local aliasing', t => {
   const result = alias({
     foo: '/bar',
     pony: '/par/a/di/se.js',
@@ -69,8 +84,7 @@ test(t => {
   t.is(resolved4, '/par/a/di/se.js');
 });
 
-// Test for the resolve property
-test(t => {
+test('Test for the resolve property', t => {
   const result = alias({
     ember: './folder/hipster',
     resolve: ['.js', '.jsx'],