Use polyfills directly

packages/server/src/jsRunner/bundles/bson-polyfills.ivm.bundle.js

@@ -1,8 +1,81 @@
-function atob(...args) {
-  return atobCB(...args)
-}
-function btoa(...args) {
-  return btoaCB(...args)
+if (typeof btoa !== "function") {
+  var chars = {
+    ascii: function () {
+      return "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
+    },
+    indices: function () {
+      if (!this.cache) {
+        this.cache = {}
+        var ascii = chars.ascii()
+
+        for (var c = 0; c < ascii.length; c++) {
+          var chr = ascii[c]
+          this.cache[chr] = c
+        }
+      }
+      return this.cache
+    },
+  }
+
+  function atob(b64) {
+    var indices = chars.indices(),
+      pos = b64.indexOf("="),
+      padded = pos > -1,
+      len = padded ? pos : b64.length,
+      i = -1,
+      data = ""
+
+    while (i < len) {
+      var code =
+        (indices[b64[++i]] << 18) |
+        (indices[b64[++i]] << 12) |
+        (indices[b64[++i]] << 6) |
+        indices[b64[++i]]
+      if (code !== 0) {
+        data += String.fromCharCode(
+          (code >>> 16) & 255,
+          (code >>> 8) & 255,
+          code & 255
+        )
+      }
+    }
+
+    if (padded) {
+      data = data.slice(0, pos - b64.length)
+    }
+
+    return data
+  }
+
+  function btoa(data) {
+    var ascii = chars.ascii(),
+      len = data.length - 1,
+      i = -1,
+      b64 = ""
+
+    while (i < len) {
+      var code =
+        (data.charCodeAt(++i) << 16) |
+        (data.charCodeAt(++i) << 8) |
+        data.charCodeAt(++i)
+      b64 +=
+        ascii[(code >>> 18) & 63] +
+        ascii[(code >>> 12) & 63] +
+        ascii[(code >>> 6) & 63] +
+        ascii[code & 63]
+    }
+
+    var pads = data.length % 3
+    if (pads > 0) {
+      b64 = b64.slice(0, pads - 3)
+
+      while (b64.length % 4 !== 0) {
+        b64 += "="
+      }
+    }
+
+    return b64
+  }
 }
 
 class TextDecoder {