Fix function isBase64 (#117)

* fix function isBase64
* Remove is-base64 dependency

---------

Co-authored-by: Michael Heap <[email protected]>

Author: leey00nsu

create-or-update-files.js

@@ -1,4 +1,32 @@
-const isBase64 = require("is-base64");
+function isBase64(str) {
+  var notBase64 = /[^A-Z0-9+\/=]/i;
+  const isString = (typeof str === 'string' || str instanceof String);
+
+  if (!isString) {
+    let invalidType;
+    if (str === null) {
+      invalidType = 'null';
+    } else {
+      invalidType = typeof str;
+      if (invalidType === 'object' && str.constructor && str.constructor.hasOwnProperty('name')) {
+        invalidType = str.constructor.name;
+      } else {
+        invalidType = `a ${invalidType}`;
+      }
+    }
+    throw new TypeError(`Expected string but received ${invalidType}.`);
+  }
+
+  const len = str.length;
+  if (!len || len % 4 !== 0 || notBase64.test(str)) {
+    return false;
+  }
+  const firstPaddingChar = str.indexOf('=');
+  return firstPaddingChar === -1 ||
+    firstPaddingChar === len - 1 ||
+    (firstPaddingChar === len - 2 && str[len - 1] === '=');
+}
+
 module.exports = function (octokit, opts) {
   return new Promise(async (resolve, reject) => {
     // Up front validation

package-lock.json

@@ -25,7 +25,6 @@
     "nock": "^13.3.3"
   },
   "dependencies": {
-    "is-base64": "^1.1.0"
   },
   "peerDependencies": {
     "@octokit/rest": ">=20.0.1"