Merge remote-tracking branch 'kristofdegrave/nullPropagation' into feat-optional-chaining

src/parser/expression.js

@@ -284,14 +284,23 @@ pp.parseSubscripts = function (base, startPos, startLoc, noCalls) {
       node.object = base;
       node.callee = this.parseNoCallExpr();
       return this.parseSubscripts(this.finishNode(node, "BindExpression"), startPos, startLoc, noCalls);
-    } else if (this.eat(tt.question)) {
-      const node = this.startNodeAt(startPos, startLoc);
-      node.object = base;
-      node.optional = true;
-      this.next();
-      node.property = this.parseIdentifier(true);
-      node.computed = false;
-      base = this.finishNode(node, "MemberExpression");
+    } else if (this.eat(tt.questionDot)) {
+      base.optional = true;
+
+      if (this.eat(tt.bracketL)) {
+        const node = this.startNodeAt(startPos, startLoc);
+        node.object = base;
+        node.property = this.parseExpression();
+        node.computed = true;
+        this.expect(tt.bracketR);
+        base = this.finishNode(node, "MemberExpression");
+      } else {
+        const node = this.startNodeAt(startPos, startLoc);
+        node.object = base;
+        node.property = this.parseIdentifier(true);
+        node.computed = false;
+        base = this.finishNode(node, "MemberExpression");
+      }
     } else if (this.eat(tt.dot)) {
       const node = this.startNodeAt(startPos, startLoc);
       node.object = base;
@@ -303,6 +312,7 @@ pp.parseSubscripts = function (base, startPos, startLoc, noCalls) {
       node.object = base;
       node.property = this.parseExpression();
       node.computed = true;
+      delete node.nullPropagation;
       this.expect(tt.bracketR);
       base = this.finishNode(node, "MemberExpression");
     } else if (!noCalls && this.match(tt.parenL)) {

src/tokenizer/index.js

@@ -391,6 +391,18 @@ export default class Tokenizer {
     return this.finishOp(code === 61 ? tt.eq : tt.prefix, 1);
   }
 
+  readToken_question() { // '?'
+    const next = this.input.charCodeAt(this.state.pos + 1);
+    if (next === 46) { // 46 = question '.'
+      this.state.pos += 2;
+      return this.finishToken(tt.questionDot);
+    }
+    else {
+      ++this.state.pos;
+      return this.finishToken(tt.question);
+    }
+  }
+
   getTokenFromCode(code) {
     switch (code) {
       // The interpretation of a dot depends on whether it is followed
@@ -425,7 +437,7 @@ export default class Tokenizer {
           return this.finishToken(tt.colon);
         }
 
-      case 63: ++this.state.pos; return this.finishToken(tt.question);
+      case 63: return this.readToken_question();
       case 64: ++this.state.pos; return this.finishToken(tt.at);
 
       case 96: // '`'
@@ -844,7 +856,7 @@ export default class Tokenizer {
     const type = this.state.type;
     let update;
 
-    if (type.keyword && prevType === tt.dot) {
+    if (type.keyword && (prevType === tt.dot || prevType === tt.questionDot)) {
       this.state.exprAllowed = false;
     } else if (update = type.updateContext) {
       update.call(this, prevType);

src/tokenizer/types.js

@@ -75,6 +75,7 @@ export const types = {
   doubleColon: new TokenType("::", { beforeExpr }),
   dot: new TokenType("."),
   question: new TokenType("?", { beforeExpr }),
+  questionDot: new TokenType("?."),
   arrow: new TokenType("=>", { beforeExpr }),
   template: new TokenType("template"),
   ellipsis: new TokenType("...", { beforeExpr }),