Add url-safe-base64 npm module declarations (#25418)

* feat(types): add url-safe-base64 npm module declarations

* chore: fix name and URL

types/url-safe-base64/index.d.ts

@@ -0,0 +1,14 @@
+// Type definitions for url-safe-base64 1.1
+// Project: https://github.com/commenthol/url-safe-base64#readme
+// Definitions by: John Wright <https://github.com/johngeorgewright>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+export function decode(safe: string): string;
+
+export function encode(base64: string): string;
+
+export function isBase64(string: string): string;
+
+export function isUrlSafeBase64(string: string): string;
+
+export function trim(string: string): string;

types/url-safe-base64/tsconfig.json

@@ -0,0 +1,23 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true,
+        "strictFunctionTypes": true
+    },
+    "files": [
+        "index.d.ts",
+        "url-safe-base64-tests.ts"
+    ]
+}

types/url-safe-base64/tslint.json

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

types/url-safe-base64/url-safe-base64-tests.ts

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+import { decode, encode, isBase64, isUrlSafeBase64, trim } from 'url-safe-base64';
+
+const safe = encode('A/B+C==');
+// > 'A-B_C..'
+trim(safe);
+// > 'A-B_C'
+const base64 = decode(safe);
+// > 'A/B+C=='
+isBase64(base64);
+// > true
+isBase64(safe);
+// > false
+isUrlSafeBase64(base64);
+// > false
+isUrlSafeBase64(safe);
+// > true