2 files changed, 46 insertions, 1 deletions
diff --git a/cli/tsc/99_main_compiler.js b/cli/tsc/99_main_compiler.js
index 6d47b6ac7..362fdd762 100644
--- a/cli/tsc/99_main_compiler.js
+++ b/cli/tsc/99_main_compiler.js
@@ -72,6 +72,43 @@ delete Object.prototype.__proto__;
     }
   }
 
+  // deno-fmt-ignore
+  const base64abc = [
+    "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", 
+    "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a", "b", "c", "d", 
+    "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", 
+    "t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4", "5", "6", "7", 
+    "8", "9", "+", "/",
+  ];
+
+  /** Taken from https://deno.land/std/encoding/base64.ts */
+  function convertToBase64(data) {
+    const uint8 = core.encode(data);
+    let result = "",
+      i;
+    const l = uint8.length;
+    for (i = 2; i < l; i += 3) {
+      result += base64abc[uint8[i - 2] >> 2];
+      result += base64abc[((uint8[i - 2] & 0x03) << 4) | (uint8[i - 1] >> 4)];
+      result += base64abc[((uint8[i - 1] & 0x0f) << 2) | (uint8[i] >> 6)];
+      result += base64abc[uint8[i] & 0x3f];
+    }
+    if (i === l + 1) {
+      // 1 octet yet to write
+      result += base64abc[uint8[i - 2] >> 2];
+      result += base64abc[(uint8[i - 2] & 0x03) << 4];
+      result += "==";
+    }
+    if (i === l) {
+      // 2 octets yet to write
+      result += base64abc[uint8[i - 2] >> 2];
+      result += base64abc[((uint8[i - 2] & 0x03) << 4) | (uint8[i - 1] >> 4)];
+      result += base64abc[(uint8[i - 1] & 0x0f) << 2];
+      result += "=";
+    }
+    return result;
+  }
+
   // In the case of the LSP, this is initialized with the assets
   // when snapshotting and never added to or removed after that.
   /** @type {Map<string, ts.SourceFile>} */
@@ -485,6 +522,14 @@ delete Object.prototype.__proto__;
    * @param {Request} request
    */
   function exec({ config, debug: debugFlag, rootNames }) {
+    // https://github.com/microsoft/TypeScript/issues/49150
+    ts.base64encode = function (host, input) {
+      if (host && host.base64encode) {
+        return host.base64encode(input);
+      }
+      return convertToBase64(input);
+    };
+
     setLogDebug(debugFlag, "TS");
     performanceStart();
     debug(">>> exec start", { rootNames });
diff --git a/cli/tsc/compiler.d.ts b/cli/tsc/compiler.d.ts
index e84484884..7d935434b 100644
--- a/cli/tsc/compiler.d.ts
+++ b/cli/tsc/compiler.d.ts
@@ -8,7 +8,7 @@ declare global {
   namespace ts {
     var libs: string[];
     var libMap: Map<string, string>;
-
+    var base64encode: (host: ts.CompilerHost, input: string) => string;
     interface SourceFile {
       version?: string;
     }