From cbb72de41abf1afd01f7234ba0084efbf0adf80a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Chopin?= <seb@nuxtjs.com>
Date: Mon, 7 Dec 2020 18:04:28 +0100
Subject: [PATCH] feat: add `cleanDoubleSlashes` (#2)

---
 README.md                | 11 +++++++++++
 src/index.ts             |  4 ++++
 test/doubleSlash.test.ts | 17 +++++++++++++++++
 test/join.test.ts        |  1 +
 4 files changed, 33 insertions(+)
 create mode 100644 test/doubleSlash.test.ts

diff --git a/README.md b/README.md
index a04bbe71..0006ded0 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,17 @@ Ensures url does not ends with a trailing slash
 withoutTrailingSlash('/foo/')
 ```
 
+### `cleanDoubleSlashes`
+
+Ensures url does not have double slash (except for protocol)
+
+```ts
+// Result: /foo/bar/
+cleanDoubleSlashes('//foo//bar//')
+// Result: http://example.com/analyze/http://localhost:3000/
+cleanDoubleSlashes('http://example.com/analyze//http://localhost:3000//')
+```
+
 ## License
 
 MIT. Made with 💖
diff --git a/src/index.ts b/src/index.ts
index 462a7aea..a607c914 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -13,6 +13,10 @@ export function withTrailingSlash (input: string = '/'): string {
   return input.endsWith('/') ? input : (input + '/')
 }
 
+export function cleanDoubleSlashes (input: string = '/'): string {
+  return input.split('://').map(str => str.replace(/\/{2,}/g, '/')).join('://')
+}
+
 export function hasProtocol (inputStr: string): boolean {
   return /\w+:\//.test(inputStr)
 }
diff --git a/test/doubleSlash.test.ts b/test/doubleSlash.test.ts
new file mode 100644
index 00000000..a4af3e89
--- /dev/null
+++ b/test/doubleSlash.test.ts
@@ -0,0 +1,17 @@
+// @ts-nocheck
+import { cleanDoubleSlashes } from '../src'
+
+describe('cleanDoubleSlashes', () => {
+  const tests = {
+    '//foo//bar//': '/foo/bar/',
+    'http://foo.com//': 'http://foo.com/',
+    'http://foo.com/bar//foo/': 'http://foo.com/bar/foo/',
+    'http://example.com/analyze//http://localhost:3000//': 'http://example.com/analyze/http://localhost:3000/'
+  }
+
+  for (const input in tests) {
+    test(input, () => {
+      expect(cleanDoubleSlashes(input)).toBe(tests[input])
+    })
+  }
+})
diff --git a/test/join.test.ts b/test/join.test.ts
index 80100e70..eb36990b 100644
--- a/test/join.test.ts
+++ b/test/join.test.ts
@@ -7,6 +7,7 @@ describe('joinURL', () => {
     { input: ['a'], out: '/a' },
     { input: ['a', 'b'], out: '/a/b' },
     { input: ['a', 'b/', 'c'], out: '/a/b/c' },
+    { input: ['a', 'b/', '/c'], out: '/a/b/c' },
     { input: ['/a?foo=bar#123', 'b/', 'c/'], out: '/a/b/c/?foo=bar#123' },
     { input: ['http://foo.com', 'a'], out: 'http://foo.com/a' }
   ]