feat(std/encoding): add base64 (#5811)

1 files changed, 41 insertions, 0 deletions

diff --git a/std/encoding/base64.ts b/std/encoding/base64.ts
new file mode 100644
index 000000000..2f74c8df0
--- /dev/null
+++ b/std/encoding/base64.ts
@@ -0,0 +1,41 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+/**
+ * Converts given data with base64 encoding
+ * @param data input to encode
+ */
+export function encode(data: string | ArrayBuffer): string {
+  if (typeof data === "string") {
+    return window.btoa(data);
+  } else {
+    const d = new Uint8Array(data);
+    let dataString = "";
+    for (let i = 0; i < d.length; ++i) {
+      dataString += String.fromCharCode(d[i]);
+    }
+
+    return window.btoa(dataString);
+  }
+}
+
+/**
+ * Converts given base64 encoded data back to original
+ * @param data input to decode
+ */
+export function decode(data: string): ArrayBuffer {
+  const binaryString = decodeString(data);
+  const binary = new Uint8Array(binaryString.length);
+  for (let i = 0; i < binary.length; ++i) {
+    binary[i] = binaryString.charCodeAt(i);
+  }
+
+  return binary.buffer;
+}
+
+/**
+ * Decodes data assuming the output is in string type
+ * @param data input to decode
+ */
+export function decodeString(data: string): string {
+  return window.atob(data);
+}