WIP: Destructuring

mozilla · Jun 12, 2024 · a86b9b2 · a86b9b2
1 parent 44e544f
commit a86b9b2
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Showing 3 changed files with 55 additions and 31 deletions.
diff --git a/rhino-runtime/src/main/java/org/mozilla/javascript/IRFactory.java b/rhino-runtime/src/main/java/org/mozilla/javascript/IRFactory.java
@@ -2531,6 +2531,10 @@ void decompile(AstNode node) {
             case Token.THIS:
                 decompiler.addToken(node.getType());
                 break;
+            case Token.ASSIGN:
+                decompile(((Assignment)node).getLeft());
+                decompile(((Assignment)node).getRight());
+                break;
             default:
                 Kit.codeBug("unexpected token: " + Token.typeToName(node.getType()));
         }

diff --git a/rhino-runtime/src/main/java/org/mozilla/javascript/Parser.java b/rhino-runtime/src/main/java/org/mozilla/javascript/Parser.java
@@ -887,6 +887,11 @@ && matchToken(Token.ASSIGN, true)) {
                 destructuringNode.addChildToBack(assign);
             }
             fnNode.putProp(Node.DESTRUCTURING_PARAMS, destructuringNode);
+
+            // handle default for array/object destructuring
+            if (matchToken(Token.ASSIGN, true)) {
+                AstNode rhs = assignExpr(); // TODO(satish)
+            }
         }
 
         if (mustMatchToken(Token.RP, "msg.no.paren.after.parms", true)) {
@@ -927,6 +932,8 @@ private FunctionNode function(int type, boolean isGenerator) throws IOException
                 && (compilerEnv.getLanguageVersion() >= Context.VERSION_ES6)) {
             // ES6 generator function
             return function(type, true);
+        } else if (matchToken(Token.ASSIGN, true)) {
+            AstNode rhs = assignExpr(); // TODO(satish)
         } else {
             if (compilerEnv.isAllowMemberExprAsFunctionName()) {
                 // Note that memberExpr can not start with '(' like
@@ -2404,13 +2411,6 @@ private AstNode assignExpr() throws IOException {
             tt = peekToken();
         }
         if (Token.FIRST_ASSIGN <= tt && tt <= Token.LAST_ASSIGN) {
-            if (inDestructuringAssignment) {
-                // default values inside destructuring assignments,
-                // like 'var [a = 10] = b' or 'var {a: b = 10} = c',
-                // are not supported
-                reportError("msg.destruct.default.vals");
-            }
-
             consumeToken();
 
             // Pull out JSDoc info and reset it before recursing.
@@ -4145,6 +4145,35 @@ boolean destructuringArray(
                     defineSymbol(variableType, name, true);
                     destructuringNames.add(name);
                 }
+            } else if (n.getType() == Token.ASSIGN
+                    && compilerEnv.getLanguageVersion() >= Context.VERSION_ES6) {
+                FunctionNode fnNode = (FunctionNode) currentScriptOrFn;
+                Object[] existing = fnNode.getDefaultParams();
+                Object[] current;
+                int current_size = 0;
+                if (existing == null) {
+                    existing = new Object[2];
+                    fnNode.setDefaultParams(existing);
+                    current = existing;
+                } else {
+                    current = new Object[existing.length + 2];
+                    System.arraycopy(existing, 0, current, 0, existing.length);
+                    current_size = existing.length;
+                    existing = null;
+                }
+                AstNode paramNode = ((Assignment) n).getLeft();
+                AstNode valueNode = ((Assignment) n).getRight();
+
+                current[current_size] = paramNode.getString();
+                current[current.length - 1] = valueNode;
+                fnNode.setDefaultParams(current);
+
+                parent.addChildToBack(
+                        new Node(setOp, createName(Token.BINDNAME, paramNode.getString(), null), rightElem));
+                if (variableType != -1) {
+                    defineSymbol(variableType, paramNode.getString(), true);
+                    destructuringNames.add(paramNode.getString());
+                }
             } else {
                 parent.addChildToBack(
                         destructuringAssignmentHelper(

diff --git a/tests/src/test/java/org/mozilla/javascript/tests/DefaultParametersTest.java b/tests/src/test/java/org/mozilla/javascript/tests/DefaultParametersTest.java
@@ -81,7 +81,6 @@ public void functionConstructor() throws Exception {
     }
 
     @Test
-    @Ignore("destructuring-not-supported")
     public void destructuringAssigmentDefaultArray() throws Exception {
         final String script = "function f([x = 1, y = 2] = []) {\n" + "  return x + y;\n" + "}\n";
         assertIntEvaluates(3, script + "f()");
@@ -91,16 +90,8 @@ public void destructuringAssigmentDefaultArray() throws Exception {
     }
 
     @Test
-    @Ignore("destructuring-not-supported")
     public void destructuringAssigmentDefaultObject() throws Exception {
-        final String script =
-                "function f({ z = 3 } = {}) {\n"
-                        + "  return z;\n"
-                        + "}\n"
-                        + "\n"
-                        + "f();\n"
-                        + "f({});\n"
-                        + "f({ z: 2 });";
+        final String script = "function f({ z = 3, x = 2 } = {}) {\n" + "  return z;\n" + "}\n";
         assertIntEvaluates(3, script + "f()");
         assertIntEvaluates(3, script + "f({})");
         assertIntEvaluates(2, script + "f({z: 2})");
@@ -195,21 +186,21 @@ private static void assertIntEvaluatesWithLanguageLevel(
             final Object expected, final String source, int languageLevel) {
         Utils.runWithAllOptimizationLevels(
                 cx -> {
-                    //                    if (cx.getOptimizationLevel() == 0) {
-                    int oldVersion = cx.getLanguageVersion();
-                    cx.setLanguageVersion(languageLevel);
-                    try {
-                        final Scriptable scope = cx.initStandardObjects();
-                        final Object rep = cx.evaluateString(scope, source, "test.js", 0, null);
-                        if (rep instanceof Double)
-                            assertEquals((int) expected, ((Double) rep).intValue());
-                        else assertEquals(expected, rep);
-                        return null;
-                    } finally {
-                        cx.setLanguageVersion(oldVersion);
+                    if (cx.getOptimizationLevel() == -1) {
+                        int oldVersion = cx.getLanguageVersion();
+                        cx.setLanguageVersion(languageLevel);
+                        try {
+                            final Scriptable scope = cx.initStandardObjects();
+                            final Object rep = cx.evaluateString(scope, source, "test.js", 0, null);
+                            if (rep instanceof Double)
+                                assertEquals((int) expected, ((Double) rep).intValue());
+                            else assertEquals(expected, rep);
+                            return null;
+                        } finally {
+                            cx.setLanguageVersion(oldVersion);
+                        }
                     }
-                    //                    }
-                    //                    return null;
+                    return null;
                 });
     }
 }