Improve rest/spread emit for symbols

Previously, symbols were not handled.

Author: sandersn

src/compiler/emitter.ts

@@ -38,6 +38,9 @@ var __assign = (this && this.__assign) || Object.assign || function(t) {
         s = arguments[i];
         for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
             t[p] = s[p];
+        if (typeof Object.getOwnPropertySymbols === "function")
+            for (var i = 0, s = Object.getOwnPropertySymbols(s); i < s.length; i++)
+                t[i] = s[i];
     }
     return t;
 };`;
@@ -47,6 +50,9 @@ var __rest = (this && this.__rest) || function (s, e) {
     var t = {};
     for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
         t[p] = s[p];
+    if (typeof Object.getOwnPropertySymbols === "function")
+        for (var i = 0, s = Object.getOwnPropertySymbols(s); i < s.length; i++) if (e.indexOf(s[i]) > 0)
+            t[i] = s[i];
     return t;
 };`;
 

src/compiler/transformers/destructuring.ts

@@ -428,7 +428,14 @@ namespace ts {
                 }
                 if (isComputedPropertyName(getPropertyName(element))) {
                     // get the temp name and put that in there instead, like `_tmp + ""`
-                    propertyNames.push(createBinary(computedTempVariables.shift(), SyntaxKind.PlusToken, createLiteral("")));
+                    const temp = computedTempVariables.shift();
+                    propertyNames.push(createConditional(createBinary(createTypeOf(temp),
+                                                                      SyntaxKind.EqualsEqualsEqualsToken,
+                                                                      createLiteral("symbol")),
+                                                         createToken(SyntaxKind.QuestionToken),
+                                                         temp,
+                                                         createToken(SyntaxKind.ColonToken),
+                                                         createBinary(temp, SyntaxKind.PlusToken, createLiteral(""))));
                 }
                 else {
                     const propName = getTextOfPropertyName(getPropertyName(element));