Add types to the 'b2a' NPM package (#35363)

* Add b2a types

* Update tsconfig.json

* b2a build fixes

types/b2a/b2a-tests.ts

@@ -0,0 +1,4 @@
+import { btoa, atob } from "b2a";
+
+const b64 = btoa ("foo");
+const text = atob (b64);

types/b2a/index.d.ts

@@ -0,0 +1,19 @@
+// Type definitions for b2a 1.0
+// Project: https://github.com/kaelzhang/b2a#readme
+// Definitions by: PatPL <https://github.com/PatPL>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+/**
+ * Converts base64 string back into original text
+ */
+declare function atob(base64: string): string;
+
+/**
+ * Converts text into base64 string
+ */
+declare function btoa(text: string): string;
+
+export {
+    atob,
+    btoa
+};

types/b2a/tsconfig.json

@@ -0,0 +1,23 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "b2a-tests.ts"
+    ]
+}

types/b2a/tslint.json

@@ -0,0 +1 @@
+{ "extends": "dtslint/dt.json" }