initial commit

.gitignore

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+/dist
+node_modules
+

LICENSE

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+Copyright (c) 2024 Supabase, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+# base64url
+
+This is a pure TypeScript [Base64-URL](https://en.wikipedia.org/wiki/Base64) encoder/decoder for JavaScript strings
+with [UTF-8](https://en.wikipedia.org/wiki/UTF-8) support.
+
+If you've found it, you're already aware that:
+
+- [btoa](https://developer.mozilla.org/en-US/docs/Web/API/btoa) and [atob](https://developer.mozilla.org/en-US/docs/Web/API/atob) only work on ASCII strings, and they're not always
+  available in cool new JS runtimes
+- [Buffer](https://nodejs.org/api/buffer.html) is only in Node.js
+- [TextEncoder](https://developer.mozilla.org/en-US/docs/Web/API/TextEncoder) only works in browsers
+
+This implementation allows you to encode any JavaScript string (emojis and
+multi-byte characters allowed!) to and from UTF-8 and then encode it as
+Base64-URL. It's great for:
+
+- Working with JWTs on any JS runtime
+- Encoding JavaScript strings to UTF-8 when serializing or parsing binary
+  formats
+
+It's a no-dependencies / no-depends library. Just copy the `src/base64url.ts`
+file in your project. It's mostly finished software, so it's unlikely you'll
+need to update it.
+
+## Use
+
+### Base64-URL
+
+To encode to Base64-URL:
+
+```typescript
+import { stringToBase64URL } from "./base64url";
+
+stringToBase64URL("This will be encoded to UTF-8 then Base64-URL");
+```
+
+To decode from Base64-URL:
+
+```typescript
+import { stringFromBase64URL } from "./base64url";
+
+stringFromBase64URL(
+  "VGhpcyB3aWxsIGJlIGVuY29kZWQgdG8gVVRGLTggdGhlbiBCYXNlNjQtVVJM",
+);
+```
+
+### UTF-8
+
+To encode a string to UTF-8:
+
+```typescript
+import { stringToUTF8 } from "./base64url";
+
+stringToUTF8("This will be encoded as UTF-8", (byte: number) => {
+  // write this byte to a stream or buffer
+});
+```
+
+To decode UTF-8 bytes to a string:
+
+```typescript
+import { stringFromUTF8 } from "./base64url";
+
+const result: string[] = [];
+const state = { utf8seq: 0, codepoint: 0 };
+
+const onCodepoint = (codepoint: number) => {
+  result.push(String.fromCodePoint(codepoint));
+};
+
+for (let byte of buffer) {
+  // buffer holds all the UTF-8 bytes,
+  // call this function for each byte
+  stringFromUTF8(byte, state, onCodepoint);
+}
+
+const string = result.join("");
+```