It seems like a struct named Map could shadow the scope of window.Map and cause unexpected behavior.

tomconnell-wf · tomconnell-wf · commit 156e55f1a88f · 2022-08-17T15:20:21.000-06:00
That's my hunch anyway. The code at https://github.com/gopherjs/gopherjs/blob/a4630ec28c790dd1be785f097d0268c4aa4a423f/nosync/map.go#L37 was making an object that didn't have a `.get` function. This fixes it. The before Javascript: ``` Map.ptr.prototype.LoadOrStore = function(key, value) { var _entry, _key, _tmp, _tmp$1, _tmp$2, _tmp$3, _tuple, actual, key, loaded, m, ok, value, value$1, x; actual = $ifaceNil; loaded = false; m = this; _tuple = (x = m.m, (_entry = typeof x.get === "function" ? x.get($emptyInterface.keyFor(key)) : undefined, _entry !== undefined ? [_entry.v, true] : [$ifaceNil, false])); value$1 = _tuple[0]; ok = _tuple[1]; if (ok) { _tmp = value$1; _tmp$1 = true; actual = _tmp; loaded = _tmp$1; return [actual, loaded]; } if (m.m === false) { m.m = new Map(); } _key = key; (m.m || $throwRuntimeError("assignment to entry in nil map")).set($emptyInterface.keyFor(_key), { k: _key, v: value }); _tmp$2 = value; _tmp$3 = false; actual = _tmp$2; loaded = _tmp$3; return [actual, loaded]; }; ```
diff --git a/compiler/expressions.go b/compiler/expressions.go
@@ -931,9 +931,9 @@ func (fc *funcContext) translateBuiltin(name string, sig *types.Signature, args
 			return fc.formatExpr("$makeSlice(%s, %f)", t, args[1])
 		case *types.Map:
 			if len(args) == 2 && fc.pkgCtx.Types[args[1]].Value == nil {
-				return fc.formatExpr(`((%1f < 0 || %1f > 2147483647) ? $throwRuntimeError("makemap: size out of range") : new Map())`, args[1])
+				return fc.formatExpr(`((%1f < 0 || %1f > 2147483647) ? $throwRuntimeError("makemap: size out of range") : new window.Map())`, args[1])
 			}
-			return fc.formatExpr(`new Map()`)
+			return fc.formatExpr(`new window.Map()`)
 		case *types.Chan:
 			length := "0"
 			if len(args) == 2 {
