@babel/eslint-parser: fix BigIntLiteral node to match ESTree spec

eslint/babel-eslint-parser/package.json

@@ -34,6 +34,7 @@
     "@babel/plugin-proposal-nullish-coalescing-operator": "^7.0.0",
     "@babel/plugin-proposal-optional-chaining": "^7.0.0",
     "@babel/plugin-proposal-pipeline-operator": "^7.0.0",
+    "@babel/plugin-syntax-bigint": "^7.7.4",
     "@babel/plugin-syntax-dynamic-import": "^7.0.0",
     "@babel/plugin-syntax-export-default-from": "^7.0.0",
     "@babel/plugin-syntax-export-namespace-from": "^7.0.0",

eslint/babel-eslint-parser/src/babylon-to-espree/convertAST.js

@@ -70,7 +70,6 @@ const astTransformVisitor = {
     }
 
     // modules
-
     if (path.isImportDeclaration()) {
       delete node.isType;
     }

eslint/babel-eslint-parser/src/babylon-to-espree/convertToken.js

@@ -77,6 +77,9 @@ export default function(token, tt, source) {
       flags: value.flags,
     };
     token.value = `/${value.pattern}/${value.flags}`;
+  } else if (type === tt.bigint) {
+    token.type = "Numeric";
+    token.value = `${token.value}n`;
   }
 
   return token;

eslint/babel-eslint-parser/test/babel-eslint-parser.js

@@ -27,7 +27,7 @@ function parseAndAssertSame(code) {
     loc: true,
     range: true,
     comment: true,
-    ecmaVersion: 2018,
+    ecmaVersion: 2020,
     sourceType: "module",
   });
   const babylonAST = parseForESLint(code, {
@@ -518,5 +518,11 @@ describe("babylon-to-espree", () => {
         }
       `);
     });
+
+    it("BigInt", () => {
+      parseAndAssertSame(`
+        const a = 1n;
+      `);
+    });
   });
 });

eslint/babel-eslint-parser/test/fixtures/config/babel.config.js

@@ -17,5 +17,6 @@ module.exports = {
     "@babel/plugin-syntax-export-namespace-from",
     ["@babel/plugin-proposal-decorators", { decoratorsBeforeExport: false }],
     ["@babel/plugin-proposal-pipeline-operator", { proposal: "minimal" }],
+    "@babel/plugin-syntax-bigint",
   ],
 };

packages/babel-parser/src/plugins/estree.js

@@ -1,5 +1,7 @@
 // @flow
 
+/* global BigInt */
+
 import { types as tt, TokenType } from "../tokenizer/types";
 import type Parser from "../parser";
 import * as N from "../types";
@@ -31,6 +33,16 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return node;
     }
 
+    estreeParseBigIntLiteral(value: any): N.Node {
+      // https://github.com/estree/estree/blob/master/es2020.md#bigintliteral
+      // $FlowIgnore
+      const bigInt = typeof BigInt !== "undefined" ? BigInt(value) : null;
+      const node = this.estreeParseLiteral(bigInt);
+      node.bigint = String(node.value || value);
+
+      return node;
+    }
+
     estreeParseLiteral(value: any): N.Node {
       return this.parseLiteral(value, "Literal");
     }
@@ -244,13 +256,16 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
     parseExprAtom(refShorthandDefaultPos?: ?Pos): N.Expression {
       switch (this.state.type) {
-        case tt.regexp:
-          return this.estreeParseRegExpLiteral(this.state.value);
-
         case tt.num:
         case tt.string:
           return this.estreeParseLiteral(this.state.value);
 
+        case tt.regexp:
+          return this.estreeParseRegExpLiteral(this.state.value);
+
+        case tt.bigint:
+          return this.estreeParseBigIntLiteral(this.state.value);
+
         case tt._null:
           return this.estreeParseLiteral(null);
 

packages/babel-parser/src/types.js

@@ -96,7 +96,8 @@ export type Literal =
   | NullLiteral
   | StringLiteral
   | BooleanLiteral
-  | NumericLiteral;
+  | NumericLiteral
+  | BigIntLiteral;
 
 export type RegExpLiteral = NodeBase & {
   type: "RegExpLiteral",

packages/babel-parser/test/fixtures/estree/bigInt/basic/input.js

@@ -0,0 +1 @@
+const a = 1n;

packages/babel-parser/test/fixtures/estree/bigInt/basic/output.json

@@ -0,0 +1,102 @@
+{
+  "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": "VariableDeclaration",
+        "start": 0,
+        "end": 13,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 13
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 6,
+            "end": 12,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 6
+              },
+              "end": {
+                "line": 1,
+                "column": 12
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 6,
+              "end": 7,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 6
+                },
+                "end": {
+                  "line": 1,
+                  "column": 7
+                },
+                "identifierName": "a"
+              },
+              "name": "a"
+            },
+            "init": {
+              "type": "Literal",
+              "start": 10,
+              "end": 12,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 10
+                },
+                "end": {
+                  "line": 1,
+                  "column": 12
+                }
+              },
+              "value": "1",
+              "raw": "1n",
+              "bigint": "1"
+            }
+          }
+        ],
+        "kind": "const"
+      }
+    ]
+  }
+}

packages/babel-parser/test/fixtures/estree/bigInt/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    "estree",
+    "bigInt"
+  ]
+}

packages/babel-parser/test/fixtures/experimental/class-properties/arguments-in-nested-class-decorator-call-expression/options.json

@@ -1,3 +1,6 @@
 {
-  "plugins": ["classProperties", ["decorators", { "decoratorsBeforeExport": false }]]
+  "plugins": [
+    "classProperties",
+    ["decorators", { "decoratorsBeforeExport": false }]
+  ]
 }