Add support for Optional Chaining

Solo-steven · Apr 28, 2021 · 0911ad8 · 0911ad8
1 parent 70c0159
commit 0911ad8
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Showing 139 changed files with 2,268 additions and 114 deletions.
diff --git a/src/messages.ts b/src/messages.ts
@@ -27,6 +27,7 @@ export const Messages = {
     InvalidLHSInForLoop: 'Invalid left-hand side in for-loop',
     InvalidModuleSpecifier: 'Unexpected token',
     InvalidRegExp: 'Invalid regular expression',
+    InvalidTaggedTemplateOnOptionalChain: 'Invalid tagged template on optional chain',
     InvalidUnicodeEscapeSequence: 'Invalid Unicode escape sequence',
     LetInLexicalBinding: 'let is disallowed as a lexically bound name',
     MissingFromClause: 'Unexpected token',

diff --git a/src/nodes.ts b/src/nodes.ts
@@ -5,12 +5,13 @@ export type ArrayExpressionElement = Expression | SpreadElement | null;
 export type ArrayPatternElement = AssignmentPattern | BindingIdentifier | BindingPattern | RestElement | null;
 export type BindingPattern = ArrayPattern | ObjectPattern;
 export type BindingIdentifier = Identifier;
+export type ChainElement = CallExpression | ComputedMemberExpression | StaticMemberExpression;
 export type Declaration = AsyncFunctionDeclaration | ClassDeclaration | ExportDeclaration | FunctionDeclaration | ImportDeclaration | VariableDeclaration;
 export type ExportableDefaultDeclaration = BindingIdentifier | BindingPattern | ClassDeclaration | Expression | FunctionDeclaration;
 export type ExportableNamedDeclaration = AsyncFunctionDeclaration | ClassDeclaration | FunctionDeclaration | VariableDeclaration;
 export type ExportDeclaration = ExportAllDeclaration | ExportDefaultDeclaration | ExportNamedDeclaration;
 export type Expression = ArrayExpression | ArrowFunctionExpression | AssignmentExpression | AsyncArrowFunctionExpression | AsyncFunctionExpression |
-    AwaitExpression | BinaryExpression | CallExpression | ClassExpression | ComputedMemberExpression |
+    AwaitExpression | BinaryExpression | CallExpression | ChainExpression | ClassExpression | ComputedMemberExpression |
     ConditionalExpression | Identifier | FunctionExpression | Literal | NewExpression | ObjectExpression |
     RegexLiteral | SequenceExpression | StaticMemberExpression | TaggedTemplateExpression |
     ThisExpression | UnaryExpression | UpdateExpression | YieldExpression;
@@ -189,10 +190,12 @@ export class CallExpression {
     readonly type: string;
     readonly callee: Expression | Import;
     readonly arguments: ArgumentListElement[];
-    constructor(callee: Expression | Import, args: ArgumentListElement[]) {
+    readonly optional: boolean;
+    constructor(callee: Expression | Import, args: ArgumentListElement[], optional: boolean) {
         this.type = Syntax.CallExpression;
         this.callee = callee;
         this.arguments = args;
+        this.optional = optional;
     }
 }
 
@@ -207,6 +210,15 @@ export class CatchClause {
     }
 }
 
+export class ChainExpression {
+    readonly type: string;
+    readonly expression: ChainElement;
+    constructor(expression: ChainElement) {
+        this.type = Syntax.ChainExpression;
+        this.expression = expression;
+    }
+}
+
 export class ClassBody {
     readonly type: string;
     readonly body: Property[];
@@ -247,11 +259,13 @@ export class ComputedMemberExpression {
     readonly computed: boolean;
     readonly object: Expression;
     readonly property: Expression;
-    constructor(object: Expression, property: Expression) {
+    readonly optional: boolean;
+    constructor(object: Expression, property: Expression, optional: boolean) {
         this.type = Syntax.MemberExpression;
         this.computed = true;
         this.object = object;
         this.property = property;
+        this.optional = optional;
     }
 }
 
@@ -690,11 +704,13 @@ export class StaticMemberExpression {
     readonly computed: boolean;
     readonly object: Expression;
     readonly property: Expression;
-    constructor(object: Expression, property: Expression) {
+    readonly optional: boolean;
+    constructor(object: Expression, property: Expression, optional: boolean) {
         this.type = Syntax.MemberExpression;
         this.computed = false;
         this.object = object;
         this.property = property;
+        this.optional = optional;
     }
 }
 

diff --git a/src/parser.ts b/src/parser.ts
@@ -1304,23 +1304,24 @@ export class Parser {
             expr = this.inheritCoverGrammar(this.matchKeyword('new') ? this.parseNewExpression : this.parsePrimaryExpression);
         }
 
+        let hasOptional = false;
         while (true) {
-            if (this.match('.')) {
-                this.context.isBindingElement = false;
-                this.context.isAssignmentTarget = true;
-                this.expect('.');
-                const property = this.parseIdentifierName();
-                expr = this.finalize(this.startNode(startToken), new Node.StaticMemberExpression(expr, property));
+            let optional = false;
+            if (this.match('?.')) {
+                optional = true;
+                hasOptional = true;
+                this.expect('?.');
+            }
 
-            } else if (this.match('(')) {
+            if (this.match('(')) {
                 const asyncArrow = maybeAsync && (startToken.lineNumber === this.lookahead.lineNumber);
                 this.context.isBindingElement = false;
                 this.context.isAssignmentTarget = false;
                 const args = asyncArrow ? this.parseAsyncArguments() : this.parseArguments();
                 if (expr.type === Syntax.Import && args.length !== 1) {
                     this.tolerateError(Messages.BadImportCallArity);
                 }
-                expr = this.finalize(this.startNode(startToken), new Node.CallExpression(expr, args));
+                expr = this.finalize(this.startNode(startToken), new Node.CallExpression(expr, args, optional));
                 if (asyncArrow && this.match('=>')) {
                     for (let i = 0; i < args.length; ++i) {
                         this.reinterpretExpressionAsPattern(args[i]);
@@ -1333,21 +1334,41 @@ export class Parser {
                 }
             } else if (this.match('[')) {
                 this.context.isBindingElement = false;
-                this.context.isAssignmentTarget = true;
+                this.context.isAssignmentTarget = !optional;
                 this.expect('[');
                 const property = this.isolateCoverGrammar(this.parseExpression);
                 this.expect(']');
-                expr = this.finalize(this.startNode(startToken), new Node.ComputedMemberExpression(expr, property));
+                expr = this.finalize(this.startNode(startToken), new Node.ComputedMemberExpression(expr, property, optional));
 
             } else if (this.lookahead.type === Token.Template && this.lookahead.head) {
+                // Optional template literal is not included in the spec.
+                // https://github.com/tc39/proposal-optional-chaining/issues/54
+                if (optional) {
+                    this.throwUnexpectedToken(this.lookahead);
+                }
+                if (hasOptional) {
+                    this.throwError(Messages.InvalidTaggedTemplateOnOptionalChain);
+                }
                 const quasi = this.parseTemplateLiteral({ isTagged: true });
                 expr = this.finalize(this.startNode(startToken), new Node.TaggedTemplateExpression(expr, quasi));
 
+            } else if (this.match('.') || optional) {
+                this.context.isBindingElement = false;
+                this.context.isAssignmentTarget = !optional;
+                if (!optional) {
+                    this.expect('.');
+                }
+                const property = this.parseIdentifierName();
+                expr = this.finalize(this.startNode(startToken), new Node.StaticMemberExpression(expr, property, optional));
+
             } else {
                 break;
             }
         }
         this.context.allowIn = previousAllowIn;
+        if (hasOptional) {
+            return new Node.ChainExpression(expr);
+        }
 
         return expr;
     }
@@ -1370,30 +1391,50 @@ export class Parser {
         let expr = (this.matchKeyword('super') && this.context.inFunctionBody) ? this.parseSuper() :
             this.inheritCoverGrammar(this.matchKeyword('new') ? this.parseNewExpression : this.parsePrimaryExpression);
 
+        let hasOptional = false;
         while (true) {
+            let optional = false;
+            if (this.match('?.')) {
+                optional = true;
+                hasOptional = true;
+                this.expect('?.');
+            }
             if (this.match('[')) {
                 this.context.isBindingElement = false;
-                this.context.isAssignmentTarget = true;
+                this.context.isAssignmentTarget = !optional;
                 this.expect('[');
                 const property = this.isolateCoverGrammar(this.parseExpression);
                 this.expect(']');
-                expr = this.finalize(node, new Node.ComputedMemberExpression(expr, property));
-
-            } else if (this.match('.')) {
-                this.context.isBindingElement = false;
-                this.context.isAssignmentTarget = true;
-                this.expect('.');
-                const property = this.parseIdentifierName();
-                expr = this.finalize(node, new Node.StaticMemberExpression(expr, property));
+                expr = this.finalize(node, new Node.ComputedMemberExpression(expr, property, optional));
 
             } else if (this.lookahead.type === Token.Template && this.lookahead.head) {
+                // Optional template literal is not included in the spec.
+                // https://github.com/tc39/proposal-optional-chaining/issues/54
+                if (optional) {
+                    this.throwUnexpectedToken(this.lookahead);
+                }
+                if (hasOptional) {
+                    this.throwError(Messages.InvalidTaggedTemplateOnOptionalChain);
+                }
                 const quasi = this.parseTemplateLiteral({ isTagged: true });
                 expr = this.finalize(node, new Node.TaggedTemplateExpression(expr, quasi));
 
+            } else if (this.match('.') || optional) {
+                this.context.isBindingElement = false;
+                this.context.isAssignmentTarget = !optional;
+                if (!optional) {
+                    this.expect('.');
+                }
+                const property = this.parseIdentifierName();
+                expr = this.finalize(node, new Node.StaticMemberExpression(expr, property, optional));
+
             } else {
                 break;
             }
         }
+        if (hasOptional) {
+            return new Node.ChainExpression(expr);
+        }
 
         return expr;
     }

diff --git a/src/scanner.ts b/src/scanner.ts
@@ -608,6 +608,20 @@ export class Scanner {
                 ++this.index;
                 this.curlyStack.pop();
                 break;
+
+            case '?':
+                ++this.index;
+                if (this.source[this.index] === '?') {
+                    ++this.index;
+                    str = '??';
+                } if (this.source[this.index] === '.' && !/^\d$/.test(this.source[this.index + 1])) {
+                    // "?." in "foo?.3:0" should not be treated as optional chaining.
+                    // See https://github.com/tc39/proposal-optional-chaining#notes
+                    ++this.index;
+                    str = '?.';
+                }
+                break;
+
             case ')':
             case ';':
             case ',':
@@ -647,7 +661,7 @@ export class Scanner {
 
                             // 1-character punctuators.
                             str = this.source[this.index];
-                            if ('<>=!+-*%&|?^/'.indexOf(str) >= 0) {
+                            if ('<>=!+-*%&|^/'.indexOf(str) >= 0) {
                                 ++this.index;
                             }
                         }

diff --git a/src/syntax.ts b/src/syntax.ts
@@ -10,6 +10,7 @@ export const Syntax = {
     BreakStatement: 'BreakStatement',
     CallExpression: 'CallExpression',
     CatchClause: 'CatchClause',
+    ChainExpression: 'ChainExpression',
     ClassBody: 'ClassBody',
     ClassDeclaration: 'ClassDeclaration',
     ClassExpression: 'ClassExpression',

diff --git a/test/3rdparty/syntax/angular-1.2.5.json b/test/3rdparty/syntax/angular-1.2.5.json
diff --git a/test/3rdparty/syntax/backbone-1.1.0.json b/test/3rdparty/syntax/backbone-1.1.0.json
diff --git a/test/3rdparty/syntax/jquery-1.9.1.json b/test/3rdparty/syntax/jquery-1.9.1.json
diff --git a/test/3rdparty/syntax/jquery.mobile-1.4.2.json b/test/3rdparty/syntax/jquery.mobile-1.4.2.json
diff --git a/test/3rdparty/syntax/mootools-1.4.5.json b/test/3rdparty/syntax/mootools-1.4.5.json
diff --git a/test/3rdparty/syntax/underscore-1.5.2.json b/test/3rdparty/syntax/underscore-1.5.2.json
diff --git a/test/3rdparty/syntax/yui-3.12.0.json b/test/3rdparty/syntax/yui-3.12.0.json
diff --git a/test/api-tests.js b/test/api-tests.js
@@ -40,6 +40,7 @@ describe('esprima.Syntax', function () {
             BreakStatement: 'BreakStatement',
             CallExpression: 'CallExpression',
             CatchClause: 'CatchClause',
+            ChainExpression: 'ChainExpression',
             ClassBody: 'ClassBody',
             ClassDeclaration: 'ClassDeclaration',
             ClassExpression: 'ClassExpression',

diff --git a/test/fixtures/ES6/arrow-function/migrated_0018.tree.json b/test/fixtures/ES6/arrow-function/migrated_0018.tree.json
@@ -65,6 +65,7 @@
                         }
                     }
                 ],
+                "optional": false,
                 "range": [
                     0,
                     13

diff --git a/test/fixtures/ES6/arrow-function/migrated_0019.tree.json b/test/fixtures/ES6/arrow-function/migrated_0019.tree.json
@@ -102,6 +102,7 @@
                         }
                     }
                 ],
+                "optional": false,
                 "range": [
                     0,
                     17

diff --git a/test/fixtures/ES6/destructuring-assignment/array-pattern/member-expr-in-rest.tree.json b/test/fixtures/ES6/destructuring-assignment/array-pattern/member-expr-in-rest.tree.json
@@ -120,7 +120,8 @@
                                     "type": "Literal",
                                     "value": 0,
                                     "raw": "0"
-                                }
+                                },
+                                "optional": false
                             }
                         }
                     ]

diff --git a/test/fixtures/ES6/destructuring-assignment/array-pattern/nested-assignment.tree.json b/test/fixtures/ES6/destructuring-assignment/array-pattern/nested-assignment.tree.json
@@ -243,7 +243,8 @@
                                                 "type": "Literal",
                                                 "value": 0,
                                                 "raw": "0"
-                                            }
+                                            },
+                                            "optional": false
                                         }
                                     }
                                 ]

diff --git a/test/fixtures/ES6/destructuring-assignment/object-pattern/nested-cover-grammar.tree.json b/test/fixtures/ES6/destructuring-assignment/object-pattern/nested-cover-grammar.tree.json
@@ -513,7 +513,8 @@
                                                                                                                                                                                                         "type": "Literal",
                                                                                                                                                                                                         "value": 0,
                                                                                                                                                                                                         "raw": "0"
-                                                                                                                                                                                                    }
+                                                                                                                                                                                                    },
+                                                                                                                                                                                                    "optional": false
                                                                                                                                                                                                 }
                                                                                                                                                                                             },
                                                                                                                                                                                             "kind": "init",

diff --git a/.../fixtures/ES6/destructuring-assignment/object-pattern/object-pattern-assignment.tree.json b/.../fixtures/ES6/destructuring-assignment/object-pattern/object-pattern-assignment.tree.json
@@ -458,7 +458,8 @@
                                         "type": "Identifier",
                                         "name": "some_call"
                                     },
-                                    "arguments": []
+                                    "arguments": [],
+                                    "optional": false
                                 },
                                 "property": {
                                     "range": [
@@ -477,7 +478,8 @@
                                     },
                                     "type": "Identifier",
                                     "name": "a"
-                                }
+                                },
+                                "optional": false
                             },
                             "kind": "init",
                             "method": false,
@@ -569,7 +571,8 @@
                                     },
                                     "type": "Identifier",
                                     "name": "a"
-                                }
+                                },
+                                "optional": false
                             },
                             "kind": "init",
                             "method": false,

diff --git a/test/fixtures/ES6/lexical-declaration/let_member.tree.json b/test/fixtures/ES6/lexical-declaration/let_member.tree.json
@@ -100,7 +100,8 @@
                         },
                         "type": "Identifier",
                         "name": "let"
-                    }
+                    },
+                    "optional": false
                 },
                 "right": {
                     "range": [

diff --git a/test/fixtures/ES6/meta-property/new-target-invoke.tree.json b/test/fixtures/ES6/meta-property/new-target-invoke.tree.json
@@ -152,7 +152,8 @@
                                     "name": "target"
                                 }
                             },
-                            "arguments": []
+                            "arguments": [],
+                            "optional": false
                         }
                     }
                 ]

diff --git a/test/fixtures/ES6/meta-property/new-target-precedence.tree.json b/test/fixtures/ES6/meta-property/new-target-precedence.tree.json
@@ -170,7 +170,8 @@
                                 },
                                 "arguments": []
                             },
-                            "arguments": []
+                            "arguments": [],
+                            "optional": false
                         }
                     }
                 ]

diff --git a/test/fixtures/ES6/spread-element/call-multi-spread.tree.json b/test/fixtures/ES6/spread-element/call-multi-spread.tree.json
@@ -157,7 +157,8 @@
                             "name": "z"
                         }
                     }
-                ]
+                ],
+                "optional": false
             }
         }
     ],
-Original file line number
+Diff line change
@@ Expand Up / @@ -65,6 +65,7 @@ @@
                             }
                         }
                     ],
+                    "optional": false,
                     "range": [
 ,
@@ Expand Down @@