Add preliminary parser and code printing support for the import.meta …

…Stage 3 proposal. See: https://github.com/tc39/proposal-import-meta https://tc39.es/proposal-import-meta/ ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=258185594
google · Jul 17, 2019 · d6a732d · d6a732d
1 parent 0db7072
commit d6a732d
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Showing 15 changed files with 150 additions and 6 deletions.
diff --git a/src/com/google/javascript/jscomp/AstValidator.java b/src/com/google/javascript/jscomp/AstValidator.java
@@ -277,6 +277,10 @@ public void validateExpression(Node n) {
         validateFeature(Feature.NEW_TARGET, n);
         validateChildless(n);
         return;
+      case IMPORT_META:
+        validateFeature(Feature.IMPORT_META, n);
+        validateChildless(n);
+        return;
       case SUPER:
         validateFeature(Feature.SUPER, n);
         validateChildless(n);

diff --git a/src/com/google/javascript/jscomp/CodeGenerator.java b/src/com/google/javascript/jscomp/CodeGenerator.java
@@ -487,6 +487,10 @@ protected void add(Node n, Context context) {
         add(")");
         break;
 
+      case IMPORT_META:
+        add("import.meta");
+        break;
+
         // CLASS -> NAME,EXPR|EMPTY,BLOCK
       case CLASS:
         {

diff --git a/src/com/google/javascript/jscomp/NodeUtil.java b/src/com/google/javascript/jscomp/NodeUtil.java
@@ -1256,6 +1256,7 @@ public static int precedence(Token type) {
       case GETELEM:
       case GETPROP:
       case NEW_TARGET:
+      case IMPORT_META:
         // Data values
       case ARRAYLIT:
       case ARRAY_PATTERN:

diff --git a/src/com/google/javascript/jscomp/TypeCheck.java b/src/com/google/javascript/jscomp/TypeCheck.java
@@ -657,6 +657,7 @@ public void visit(NodeTraversal t, Node n, Node parent) {
 
       case SUPER:
       case NEW_TARGET:
+      case IMPORT_META:
       case AWAIT:
         ensureTyped(n);
         break;

diff --git a/src/com/google/javascript/jscomp/parsing/IRFactory.java b/src/com/google/javascript/jscomp/parsing/IRFactory.java
@@ -93,6 +93,7 @@
 import com.google.javascript.jscomp.parsing.parser.trees.IdentifierExpressionTree;
 import com.google.javascript.jscomp.parsing.parser.trees.IfStatementTree;
 import com.google.javascript.jscomp.parsing.parser.trees.ImportDeclarationTree;
+import com.google.javascript.jscomp.parsing.parser.trees.ImportMetaExpressionTree;
 import com.google.javascript.jscomp.parsing.parser.trees.ImportSpecifierTree;
 import com.google.javascript.jscomp.parsing.parser.trees.IndexSignatureTree;
 import com.google.javascript.jscomp.parsing.parser.trees.InterfaceDeclarationTree;
@@ -2642,6 +2643,12 @@ Node processDynamicImport(DynamicImportTree dynamicImportNode) {
       return newNode(Token.DYNAMIC_IMPORT, argument);
     }
 
+    Node processImportMeta(ImportMetaExpressionTree tree) {
+      maybeWarnForFeature(tree, Feature.MODULES);
+      maybeWarnForFeature(tree, Feature.IMPORT_META);
+      return newNode(Token.IMPORT_META);
+    }
+
     Node processTypeName(TypeNameTree tree) {
       Node typeNode;
       if (tree.segments.size() == 1) {
@@ -3153,6 +3160,8 @@ public Node process(ParseTree node) {
           return processImportSpec(node.asImportSpecifier());
         case DYNAMIC_IMPORT_EXPRESSION:
           return processDynamicImport(node.asDynamicImportExpression());
+        case IMPORT_META_EXPRESSION:
+          return processImportMeta(node.asImportMetaExpression());
 
         case ARRAY_PATTERN:
           return processArrayPattern(node.asArrayPattern());

diff --git a/src/com/google/javascript/jscomp/parsing/parser/FeatureSet.java b/src/com/google/javascript/jscomp/parsing/parser/FeatureSet.java
@@ -180,8 +180,9 @@ public enum Feature {
     // https://github.com/tc39/proposal-optional-catch-binding
     OPTIONAL_CATCH_BINDING("Optional catch binding", LangVersion.ES2019),
 
-    // Stage 3 proposal likely to be part of ES2020
+    // Stage 3 proposals likely to be part of ES2020
     DYNAMIC_IMPORT("Dynamic module import", LangVersion.ES_UNSUPPORTED),
+    IMPORT_META("import.meta", LangVersion.ES_UNSUPPORTED),
 
     // ES6 typed features that are not at all implemented in browsers
     ACCESSIBILITY_MODIFIER("accessibility modifier", LangVersion.TYPESCRIPT),

diff --git a/src/com/google/javascript/jscomp/parsing/parser/Parser.java b/src/com/google/javascript/jscomp/parsing/parser/Parser.java
@@ -70,6 +70,7 @@
 import com.google.javascript.jscomp.parsing.parser.trees.IdentifierExpressionTree;
 import com.google.javascript.jscomp.parsing.parser.trees.IfStatementTree;
 import com.google.javascript.jscomp.parsing.parser.trees.ImportDeclarationTree;
+import com.google.javascript.jscomp.parsing.parser.trees.ImportMetaExpressionTree;
 import com.google.javascript.jscomp.parsing.parser.trees.ImportSpecifierTree;
 import com.google.javascript.jscomp.parsing.parser.trees.IndexSignatureTree;
 import com.google.javascript.jscomp.parsing.parser.trees.InterfaceDeclarationTree;
@@ -392,9 +393,12 @@ private ParseTree parseAmbientNamespaceElement() {
     return parseAmbientDeclarationHelper();
   }
 
-  // https://people.mozilla.org/~jorendorff/es6-draft.html#sec-imports
   private boolean peekImportDeclaration() {
-    return peek(TokenType.IMPORT) && !peek(1, TokenType.OPEN_PAREN);
+    return peek(TokenType.IMPORT)
+        && (peekIdOrKeyword(1)
+            || peek(1, TokenType.STRING)
+            || peek(1, TokenType.OPEN_CURLY)
+            || peek(1, TokenType.STAR));
   }
 
   private ParseTree parseImportDeclaration() {
@@ -2933,7 +2937,7 @@ private boolean peekExpression() {
       case YIELD:
         return true;
       case IMPORT:
-        return peekImportCall();
+        return peekImportCall() || peekImportDot();
       default:
         return false;
     }
@@ -3515,6 +3519,10 @@ private boolean peekImportCall() {
     return peek(TokenType.IMPORT) && peek(1, TokenType.OPEN_PAREN);
   }
 
+  private boolean peekImportDot() {
+    return peek(TokenType.IMPORT) && peek(1, TokenType.PERIOD);
+  }
+
   // 11.2 Left hand side expression
   //
   // Also inlines the call expression productions
@@ -3571,7 +3579,9 @@ private boolean peekCallSuffix() {
   private ParseTree parseMemberExpressionNoNew() {
     SourcePosition start = getTreeStartLocation();
     ParseTree operand;
-    if (peekAsyncFunctionStart()) {
+    if (peekImportDot()) {
+      operand = parseImportDotMeta();
+    } else if (peekAsyncFunctionStart()) {
       operand = parseAsyncFunctionExpression();
     } else if (peekFunction()) {
       operand = parseFunctionExpression();
@@ -3635,6 +3645,14 @@ private ParseTree parseNewDotSomething() {
     return new NewTargetExpressionTree(getTreeLocation(start));
   }
 
+  private ParseTree parseImportDotMeta() {
+    SourcePosition start = getTreeStartLocation();
+    eat(TokenType.IMPORT);
+    eat(TokenType.PERIOD);
+    eatPredefinedString("meta");
+    return new ImportMetaExpressionTree(getTreeLocation(start));
+  }
+
   private ArgumentListTree parseArguments() {
     // ArgumentList :
     //   AssignmentOrSpreadExpression
@@ -4016,7 +4034,11 @@ private boolean peekId(int index) {
   }
 
   private boolean peekIdOrKeyword() {
-    TokenType type = peekType();
+    return peekIdOrKeyword(0);
+  }
+
+  private boolean peekIdOrKeyword(int index) {
+    TokenType type = peekType(index);
     return TokenType.IDENTIFIER == type || Keywords.isKeyword(type);
   }
 

diff --git a/src/com/google/javascript/jscomp/parsing/parser/trees/ImportMetaExpressionTree.java b/src/com/google/javascript/jscomp/parsing/parser/trees/ImportMetaExpressionTree.java
@@ -0,0 +1,26 @@
+/*
+ * Copyright 2019 The Closure Compiler Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.javascript.jscomp.parsing.parser.trees;
+
+import com.google.javascript.jscomp.parsing.parser.util.SourceRange;
+
+/** Represents 'new.target'. */
+public class ImportMetaExpressionTree extends ParseTree {
+  public ImportMetaExpressionTree(SourceRange location) {
+    super(ParseTreeType.IMPORT_META_EXPRESSION, location);
+  }
+}
diff --git a/src/com/google/javascript/jscomp/parsing/parser/trees/ParseTree.java b/src/com/google/javascript/jscomp/parsing/parser/trees/ParseTree.java
@@ -105,6 +105,10 @@ public DynamicImportTree asDynamicImportExpression() {
     return (DynamicImportTree) this;
   }
 
+  public ImportMetaExpressionTree asImportMetaExpression() {
+    return (ImportMetaExpressionTree) this;
+  }
+
   public LabelledStatementTree asLabelledStatement() { return (LabelledStatementTree) this; }
   public LiteralExpressionTree asLiteralExpression() { return (LiteralExpressionTree) this; }
   public MemberExpressionTree asMemberExpression() { return (MemberExpressionTree) this; }

diff --git a/src/com/google/javascript/jscomp/parsing/parser/trees/ParseTreeType.java b/src/com/google/javascript/jscomp/parsing/parser/trees/ParseTreeType.java
@@ -120,4 +120,5 @@ public enum ParseTreeType {
   NEW_TARGET_EXPRESSION,
   AWAIT_EXPRESSION,
   DYNAMIC_IMPORT_EXPRESSION,
+  IMPORT_META_EXPRESSION,
 }
diff --git a/src/com/google/javascript/rhino/IR.java b/src/com/google/javascript/rhino/IR.java
@@ -676,6 +676,10 @@ public static Node typeof(Node expr) {
     return unaryOp(Token.TYPEOF, expr);
   }
 
+  public static Node importMeta() {
+    return new Node(Token.IMPORT_META);
+  }
+
   // helper methods
 
   private static Node binaryOp(Token token, Node expr1, Node expr2) {
@@ -795,6 +799,7 @@ public static boolean mayBeExpression(Node n) {
       case GETELEM:
       case GT:
       case HOOK:
+      case IMPORT_META:
       case IN:
       case INC:
       case INSTANCEOF:

diff --git a/src/com/google/javascript/rhino/Token.java b/src/com/google/javascript/rhino/Token.java
@@ -193,6 +193,7 @@ public enum Token {
 
   DEFAULT_VALUE, // Formal parameter or destructuring element with a default value
   NEW_TARGET, // new.target
+  IMPORT_META, // import.meta
 
   // Used by type declaration ASTs
   STRING_TYPE,

diff --git a/test/com/google/javascript/jscomp/AstValidatorTest.java b/test/com/google/javascript/jscomp/AstValidatorTest.java
@@ -237,6 +237,13 @@ public void testNewTargetIsValidExpression() {
     expectValid(n, Check.EXPRESSION);
   }
 
+  @Test
+  public void testImportMetaIsValidExpression() {
+    setAcceptedLanguage(LanguageMode.UNSUPPORTED);
+    Node n = new Node(Token.IMPORT_META);
+    expectValid(n, Check.EXPRESSION);
+  }
+
   @Test
   public void testCastOnLeftSideOfAssign() {
     JSDocInfoBuilder jsdoc = new JSDocInfoBuilder(false);

diff --git a/test/com/google/javascript/jscomp/CodePrinterTest.java b/test/com/google/javascript/jscomp/CodePrinterTest.java
@@ -2746,6 +2746,14 @@ public void testNewTarget() {
     assertPrint("function f() {\nnew\n.\ntarget;\n}", "function f(){new.target}");
   }
 
+  @Test
+  public void testImportMeta() {
+    useUnsupportedFeatures = true;
+    assertPrintSame("import.meta");
+    assertPrintSame("import.meta.url");
+    assertPrintSame("console.log(import.meta.url)");
+  }
+
   @Test
   public void testGeneratorYield() {
     assertPrintSame("function*f(){yield 1}");

diff --git a/test/com/google/javascript/jscomp/parsing/ParserTest.java b/test/com/google/javascript/jscomp/parsing/ParserTest.java
@@ -32,6 +32,7 @@
 import com.google.javascript.jscomp.parsing.ParserRunner.ParseResult;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet;
 import com.google.javascript.jscomp.parsing.parser.FeatureSet.Feature;
+import com.google.javascript.rhino.IR;
 import com.google.javascript.rhino.JSDocInfo;
 import com.google.javascript.rhino.JSTypeExpression;
 import com.google.javascript.rhino.Node;
@@ -5179,6 +5180,55 @@ public void testAwaitDynamicImport() {
     }
   }
 
+  @Test
+  public void testImportMeta() {
+    mode = LanguageMode.UNSUPPORTED;
+    expectFeatures(Feature.MODULES, Feature.IMPORT_META);
+
+    Node tree = parse("import.meta");
+    assertNode(tree.getFirstFirstChild()).isEqualTo(IR.exprResult(IR.importMeta()));
+  }
+
+  @Test
+  public void testImportMeta_es5() {
+    mode = LanguageMode.ECMASCRIPT5;
+    expectFeatures(Feature.MODULES, Feature.IMPORT_META);
+
+    parseWarning(
+        "import.meta",
+        requiresLanguageModeMessage(LanguageMode.ECMASCRIPT6, Feature.MODULES),
+        unsupportedFeatureMessage(Feature.IMPORT_META));
+  }
+
+  @Test
+  public void testImportMeta_es6() {
+    mode = LanguageMode.ECMASCRIPT6;
+    expectFeatures(Feature.MODULES, Feature.IMPORT_META);
+
+    parseWarning("import.meta", unsupportedFeatureMessage(Feature.IMPORT_META));
+  }
+
+  @Test
+  public void testImportMeta_inExpression() {
+    mode = LanguageMode.UNSUPPORTED;
+    expectFeatures(Feature.MODULES, Feature.IMPORT_META);
+
+    Node propTree = parse("import.meta.url");
+    assertNode(propTree.getFirstFirstChild())
+        .isEqualTo(IR.exprResult(IR.getprop(IR.importMeta(), "url")));
+
+    Node callTree = parse("f(import.meta.url)");
+    assertNode(callTree.getFirstFirstChild())
+        .isEqualTo(IR.exprResult(IR.call(IR.name("f"), IR.getprop(IR.importMeta(), "url"))));
+  }
+
+  @Test
+  public void testImportMeta_asDotProperty() {
+    Node tree = parse("x.import.meta");
+    assertNode(tree.getFirstChild())
+        .isEqualTo(IR.exprResult(IR.getprop(IR.name("x"), "import", "meta")));
+  }
+
   private void assertNodeHasJSDocInfoWithJSType(Node node, JSType jsType) {
     JSDocInfo info = node.getJSDocInfo();
     assertWithMessage("Node has no JSDocInfo: %s", node).that(info).isNotNull();