eslint-parser: ES2020 features (#11815)

* chore: update espree test on nullish coalescing * feat: add optional chaining support * fix: adapt to estree AST shape * chore: update lockfile * add estree optional-chaining test fixtures * address review comments * chore: simplify smoke test * export * support Co-authored-by: Brian Ng <bng412@gmail.com>
babel · Jul 29, 2020 · d7347fb · d7347fb
1 parent 059e912
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diff --git a/eslint/babel-eslint-parser/package.json b/eslint/babel-eslint-parser/package.json
@@ -23,8 +23,8 @@
     "eslint": ">=6.0.0"
   },
   "dependencies": {
-    "eslint-scope": "5.0.0",
-    "eslint-visitor-keys": "^1.1.0",
+    "eslint-scope": "5.1.0",
+    "eslint-visitor-keys": "^1.3.0",
     "semver": "^6.3.0"
   },
   "devDependencies": {

diff --git a/eslint/babel-eslint-parser/src/convert/convertAST.js b/eslint/babel-eslint-parser/src/convert/convertAST.js
@@ -1,4 +1,5 @@
 import { types as t, traverse } from "@babel/core";
+import VISITOR_KEYS from "../visitor-keys";
 
 function convertNodes(ast, code) {
   const astTransformVisitor = {
@@ -81,21 +82,28 @@ function convertNodes(ast, code) {
   };
   const state = { source: code };
 
-  // Monkey patch visitor keys in order to be able to traverse the estree nodes
-  t.VISITOR_KEYS.Property = t.VISITOR_KEYS.ObjectProperty;
-  t.VISITOR_KEYS.MethodDefinition = [
-    "key",
-    "value",
-    "decorators",
-    "returnType",
-    "typeParameters",
-  ];
-
-  traverse(ast, astTransformVisitor, null, state);
-
-  // These can be safely deleted because they are not defined in the original visitor keys.
-  delete t.VISITOR_KEYS.Property;
-  delete t.VISITOR_KEYS.MethodDefinition;
+  const oldExportAllDeclarationKeys = t.VISITOR_KEYS.ExportAllDeclaration;
+
+  try {
+    // Monkey patch visitor keys in order to be able to traverse the estree nodes
+    t.VISITOR_KEYS.ChainExpression = VISITOR_KEYS.ChainExpression;
+    t.VISITOR_KEYS.Property = VISITOR_KEYS.Property;
+    t.VISITOR_KEYS.MethodDefinition = VISITOR_KEYS.MethodDefinition;
+
+    // Make sure we visit `exported` key to remove `identifierName` from loc node
+    t.VISITOR_KEYS.ExportAllDeclaration = t.VISITOR_KEYS.ExportAllDeclaration.concat(
+      "exported",
+    );
+
+    traverse(ast, astTransformVisitor, null, state);
+  } finally {
+    // These can be safely deleted because they are not defined in the original visitor keys.
+    delete t.VISITOR_KEYS.ChainExpression;
+    delete t.VISITOR_KEYS.MethodDefinition;
+    delete t.VISITOR_KEYS.Property;
+
+    t.VISITOR_KEYS.ExportAllDeclaration = oldExportAllDeclarationKeys;
+  }
 }
 
 function convertProgramNode(ast) {

diff --git a/eslint/babel-eslint-parser/src/convert/convertTokens.js b/eslint/babel-eslint-parser/src/convert/convertTokens.js
@@ -115,7 +115,6 @@ function convertToken(token, source) {
     type === tt.incDec ||
     type === tt.colon ||
     type === tt.question ||
-    type === tt.questionDot ||
     type === tt.template ||
     type === tt.backQuote ||
     type === tt.dollarBraceL ||
@@ -173,6 +172,12 @@ function convertToken(token, source) {
   } else if (type === tt.bigint) {
     token.type = "Numeric";
     token.value = `${token.value}n`;
+  } else if (type === tt.questionDot) {
+    token.value = type.label;
+  }
+  if (typeof token.type !== "string") {
+    // Acorn does not have rightAssociative
+    delete token.type.rightAssociative;
   }
 
   return token;

diff --git a/eslint/babel-eslint-parser/src/visitor-keys.js b/eslint/babel-eslint-parser/src/visitor-keys.js
@@ -1,10 +1,13 @@
 import { types as t } from "@babel/core";
 import { KEYS as ESLINT_VISITOR_KEYS } from "eslint-visitor-keys";
 
-const { VISITOR_KEYS: BABEL_VISITOR_KEYS } = t;
+/*eslint no-unused-vars: ["error", { "ignoreRestSiblings": true }]*/
+const { ExportAllDeclaration, ...BABEL_VISITOR_KEYS } = t.VISITOR_KEYS;
 
 export default Object.assign(
   {
+    ChainExpression: ESLINT_VISITOR_KEYS.ChainExpression,
+    ExportAllDeclaration: ESLINT_VISITOR_KEYS.ExportAllDeclaration,
     Literal: ESLINT_VISITOR_KEYS.Literal,
     MethodDefinition: ["decorators"].concat(
       ESLINT_VISITOR_KEYS.MethodDefinition,

diff --git a/eslint/babel-eslint-parser/test/index.js b/eslint/babel-eslint-parser/test/index.js
@@ -253,6 +253,10 @@ describe("Babel and Espree", () => {
     parseAndAssertSame('import "foo";');
   });
 
+  it("import meta", () => {
+    parseAndAssertSame("const url = import.meta.url");
+  });
+
   it("export default class declaration", () => {
     parseAndAssertSame("export default class Foo {}");
   });
@@ -273,15 +277,8 @@ describe("Babel and Espree", () => {
     parseAndAssertSame('export * from "foo";');
   });
 
-  // Espree doesn't support `export * as ns` yet
   it("export * as ns", () => {
-    const code = 'export * as Foo from "foo";';
-    const babylonAST = parseForESLint(code, {
-      eslintVisitorKeys: true,
-      eslintScopeManager: true,
-      babelOptions: BABEL_OPTIONS,
-    }).ast;
-    expect(babylonAST.tokens[1].type).toEqual("Punctuator");
+    parseAndAssertSame('export * as Foo from "foo";');
   });
 
   it("export named", () => {
@@ -292,26 +289,12 @@ describe("Babel and Espree", () => {
     parseAndAssertSame("var foo = 1;export { foo as bar };");
   });
 
-  // Espree doesn't support the optional chaining operator yet
-  it("optional chaining operator (token)", () => {
-    const code = "foo?.bar";
-    const babylonAST = parseForESLint(code, {
-      eslintVisitorKeys: true,
-      eslintScopeManager: true,
-      babelOptions: BABEL_OPTIONS,
-    }).ast;
-    expect(babylonAST.tokens[1].type).toEqual("Punctuator");
+  it("optional chaining operator", () => {
+    parseAndAssertSame("foo?.bar?.().qux()");
   });
 
-  // Espree doesn't support the nullish coalescing operator yet
-  it("nullish coalescing operator (token)", () => {
-    const code = "foo ?? bar";
-    const babylonAST = parseForESLint(code, {
-      eslintVisitorKeys: true,
-      eslintScopeManager: true,
-      babelOptions: BABEL_OPTIONS,
-    }).ast;
-    expect(babylonAST.tokens[1].type).toEqual("Punctuator");
+  it("nullish coalescing operator", () => {
+    parseAndAssertSame("foo ?? bar");
   });
 
   // Espree doesn't support the pipeline operator yet

diff --git a/eslint/babel-eslint-plugin/src/rules/no-unused-expressions.js b/eslint/babel-eslint-plugin/src/rules/no-unused-expressions.js
@@ -53,7 +53,8 @@ function isOptionalCallExpression(node) {
   return (
     !!node &&
     node.type === "ExpressionStatement" &&
-    node.expression.type === "OptionalCallExpression"
+    node.expression.type === "ChainExpression" &&
+    node.expression.expression.type === "CallExpression"
   );
 }
 

diff --git a/packages/babel-parser/src/plugins/estree.js b/packages/babel-parser/src/plugins/estree.js
@@ -388,8 +388,6 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         delete node.arguments;
         // $FlowIgnore - callee isn't optional in the type definition
         delete node.callee;
-      } else if (node.type === "CallExpression") {
-        (node: N.Node).optional = false;
       }
 
       return node;
@@ -431,10 +429,38 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return node;
     }
 
-    parseSubscript(...args) {
-      const node = super.parseSubscript(...args);
+    parseSubscript(
+      base: N.Expression,
+      startPos: number,
+      startLoc: Position,
+      noCalls: ?boolean,
+      state: N.ParseSubscriptState,
+    ) {
+      const node = super.parseSubscript(
+        base,
+        startPos,
+        startLoc,
+        noCalls,
+        state,
+      );
 
-      if (node.type === "MemberExpression") {
+      if (state.optionalChainMember) {
+        // https://github.com/estree/estree/blob/master/es2020.md#chainexpression
+        if (
+          node.type === "OptionalMemberExpression" ||
+          node.type === "OptionalCallExpression"
+        ) {
+          node.type = node.type.substring(8); // strip Optional prefix
+        }
+        if (state.stop) {
+          const chain = this.startNodeAtNode(node);
+          chain.expression = node;
+          return this.finishNode(chain, "ChainExpression");
+        }
+      } else if (
+        node.type === "MemberExpression" ||
+        node.type === "CallExpression"
+      ) {
         node.optional = false;
       }
 

diff --git a/packages/babel-parser/test/fixtures/estree/optional-chaining/optional-call-call/input.js b/packages/babel-parser/test/fixtures/estree/optional-chaining/optional-call-call/input.js
@@ -0,0 +1 @@
+(foo?.())()
diff --git a/packages/babel-parser/test/fixtures/estree/optional-chaining/optional-call-call/output.json b/packages/babel-parser/test/fixtures/estree/optional-chaining/optional-call-call/output.json
@@ -0,0 +1,41 @@
+{
+  "type": "File",
+  "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+        "expression": {
+          "type": "CallExpression",
+          "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+          "callee": {
+            "type": "ChainExpression",
+            "start":1,"end":8,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":8}},
+            "expression": {
+              "type": "CallExpression",
+              "start":1,"end":8,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":8}},
+              "callee": {
+                "type": "Identifier",
+                "start":1,"end":4,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":4},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "optional": true,
+              "arguments": []
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 0
+            }
+          },
+          "arguments": [],
+          "optional": false
+        }
+      }
+    ]
+  }
+}
diff --git a/...s/babel-parser/test/fixtures/estree/optional-chaining/optional-call-chained-call/input.js b/...s/babel-parser/test/fixtures/estree/optional-chaining/optional-call-chained-call/input.js
@@ -0,0 +1 @@
+foo?.()()
diff --git a/...abel-parser/test/fixtures/estree/optional-chaining/optional-call-chained-call/output.json b/...abel-parser/test/fixtures/estree/optional-chaining/optional-call-chained-call/output.json
@@ -0,0 +1,37 @@
+{
+  "type": "File",
+  "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+        "expression": {
+          "type": "ChainExpression",
+          "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+          "expression": {
+            "type": "CallExpression",
+            "start":0,"end":9,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":9}},
+            "callee": {
+              "type": "CallExpression",
+              "start":0,"end":7,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":7}},
+              "callee": {
+                "type": "Identifier",
+                "start":0,"end":3,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":3},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "optional": true,
+              "arguments": []
+            },
+            "optional": false,
+            "arguments": []
+          }
+        }
+      }
+    ]
+  }
+}
diff --git a/...babel-parser/test/fixtures/estree/optional-chaining/optional-call-chained-member/input.js b/...babel-parser/test/fixtures/estree/optional-chaining/optional-call-chained-member/input.js
@@ -0,0 +1 @@
+foo?.().bar
diff --git a/...el-parser/test/fixtures/estree/optional-chaining/optional-call-chained-member/output.json b/...el-parser/test/fixtures/estree/optional-chaining/optional-call-chained-member/output.json
@@ -0,0 +1,42 @@
+{
+  "type": "File",
+  "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+        "expression": {
+          "type": "ChainExpression",
+          "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+          "expression": {
+            "type": "MemberExpression",
+            "start":0,"end":11,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":11}},
+            "object": {
+              "type": "CallExpression",
+              "start":0,"end":7,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":7}},
+              "callee": {
+                "type": "Identifier",
+                "start":0,"end":3,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":3},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "optional": true,
+              "arguments": []
+            },
+            "property": {
+              "type": "Identifier",
+              "start":8,"end":11,"loc":{"start":{"line":1,"column":8},"end":{"line":1,"column":11},"identifierName":"bar"},
+              "name": "bar"
+            },
+            "computed": false,
+            "optional": false
+          }
+        }
+      }
+    ]
+  }
+}
diff --git a/packages/babel-parser/test/fixtures/estree/optional-chaining/optional-call-member/input.js b/packages/babel-parser/test/fixtures/estree/optional-chaining/optional-call-member/input.js
@@ -0,0 +1 @@
+(foo?.()).bar
diff --git a/...ages/babel-parser/test/fixtures/estree/optional-chaining/optional-call-member/output.json b/...ages/babel-parser/test/fixtures/estree/optional-chaining/optional-call-member/output.json
@@ -0,0 +1,46 @@
+{
+  "type": "File",
+  "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+        "expression": {
+          "type": "MemberExpression",
+          "start":0,"end":13,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":13}},
+          "object": {
+            "type": "ChainExpression",
+            "start":1,"end":8,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":8}},
+            "expression": {
+              "type": "CallExpression",
+              "start":1,"end":8,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":8}},
+              "callee": {
+                "type": "Identifier",
+                "start":1,"end":4,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":4},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "optional": true,
+              "arguments": []
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 0
+            }
+          },
+          "property": {
+            "type": "Identifier",
+            "start":10,"end":13,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":13},"identifierName":"bar"},
+            "name": "bar"
+          },
+          "computed": false,
+          "optional": false
+        }
+      }
+    ]
+  }
+}