Support ES2022 class-private-fields-in syntax (#1068)

FIX #1067 FEATURE: Support class private fields with the `in` operator. Co-authored-by: 成仕伟 <[email protected]>
acornjs · Sep 13, 2021 · 9cff83e · 9cff83e
1 parent 230ac74
commit 9cff83e
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Showing 4 changed files with 565 additions and 2 deletions.
diff --git a/acorn-loose/src/expression.js b/acorn-loose/src/expression.js
@@ -131,6 +131,8 @@ lp.parseMaybeUnary = function(sawUnary) {
     this.next()
     node.argument = this.parseMaybeUnary(sawUnary)
     expr = this.finishNode(node, "SpreadElement")
+  } else if (!sawUnary && this.tok.type === tt.privateId) {
+    expr = this.parsePrivateIdent()
   } else {
     expr = this.parseExprSubscripts()
     while (this.tok.type.postfix && !this.canInsertSemicolon()) {

diff --git a/acorn/src/expression.js b/acorn/src/expression.js
@@ -215,6 +215,7 @@ pp.parseExprOp = function(left, leftStartPos, leftStartLoc, minPrec, forInit) {
 }
 
 pp.buildBinary = function(startPos, startLoc, left, right, op, logical) {
+  if (right.type === "PrivateIdentifier") this.raise(right.start, "Private identifier can only be left side of binary expression")
   let node = this.startNodeAt(startPos, startLoc)
   node.left = left
   node.operator = op
@@ -244,6 +245,11 @@ pp.parseMaybeUnary = function(refDestructuringErrors, sawUnary, incDec, forInit)
       this.raiseRecoverable(node.start, "Private fields can not be deleted")
     else sawUnary = true
     expr = this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression")
+  } else if (!sawUnary && this.type === tt.privateId) {
+    if (forInit || this.privateNameStack.length === 0) this.unexpected()
+    expr = this.parsePrivateIdent()
+    // only could be private fields in 'in', such as #x in obj
+    if (this.type !== tt._in) this.unexpected()
   } else {
     expr = this.parseExprSubscripts(refDestructuringErrors, forInit)
     if (this.checkExpressionErrors(refDestructuringErrors)) return expr

diff --git a/bin/run_test262.js b/bin/run_test262.js
@@ -6,7 +6,6 @@ const parse = require("../acorn").parse
 const unsupportedFeatures = [
   "regexp-match-indices",
   "arbitrary-module-namespace-names",
-  "class-fields-private-in",
   "import-assertions"
 ];