workround IE11 issues

gfx · gfx · commit 46671b450679 · 2019-05-11T23:19:25.000+09:00
diff --git a/src/Decoder.ts b/src/Decoder.ts
@@ -29,7 +29,20 @@ type StackState = StackArrayState | StackMapState;
 const HEAD_BYTE_REQUIRED = -1;
 
 const EMPTY_VIEW = new DataView(new ArrayBuffer(0));
-const MORE_DATA = new RangeError("Insufficient data");
+
+// IE11: Just use RangeError when IE11 is obsolete.
+export const DataViewIndexOutOfBoundsError: typeof Error = (() => {
+  try {
+    // IE11: The spec says it should throw RangeError,
+    // IE11: but in IE11 it throws TypeError.
+    EMPTY_VIEW.getInt8(0);
+  } catch (e) {
+    return e.constructor;
+  }
+  throw new Error("never reached");
+})();
+
+const MORE_DATA = new DataViewIndexOutOfBoundsError("Insufficient data");
 
 export class Decoder {
   totalPos = 0;
@@ -92,7 +105,7 @@ export class Decoder {
         object = this.decodeSync();
         decoded = true;
       } catch (e) {
-        if (!(e instanceof RangeError)) {
+        if (!(e instanceof DataViewIndexOutOfBoundsError)) {
           throw e; // rethrow
         }
         // fallthrough
diff --git a/test/edge-cases.test.ts b/test/edge-cases.test.ts
@@ -1,5 +1,6 @@
 import assert from "assert";
 import { encode, decode, decodeAsync } from "../src";
+import { DataViewIndexOutOfBoundsError } from "../src/Decoder";
 
 describe("edge cases", () => {
   context("try to encode trycyclic refs", () => {
@@ -15,7 +16,7 @@ describe("edge cases", () => {
   context("try to encode non-encodable objects", () => {
     it("throws errors", () => {
       assert.throws(() => {
-        encode(Symbol("this is a symbol!"));
+        encode(() => {});
       }, /unrecognized object/i);
     });
   });
@@ -51,7 +52,8 @@ describe("edge cases", () => {
           0x92, // fixarray size=2
           0xc0, // nil
         ]);
-      }, RangeError);
+        // [IE11] A raw error thrown by DataView
+      }, DataViewIndexOutOfBoundsError);
     });
 
     it("throws errors (asynchronous)", async () => {
