Add rest/spread properties

bin/run_test262.js

@@ -9,8 +9,6 @@ const unsupportedFeatures = [
   "class-fields",
   "class-fields-private",
   "class-fields-public",
-  "object-rest",
-  "object-spread",
   "optional-catch-binding",
   "regexp-lookbehind",
   "regexp-named-groups",

src/expression.js

@@ -29,6 +29,8 @@ const pp = Parser.prototype
 // strict mode, init properties are also not allowed to be repeated.
 
 pp.checkPropClash = function(prop, propHash, refDestructuringErrors) {
+  if (this.options.ecmaVersion >= 9 && prop.type === "SpreadElement")
+    return
   if (this.options.ecmaVersion >= 6 && (prop.computed || prop.method || prop.shorthand))
     return
   let {key} = prop, name
@@ -565,6 +567,32 @@ pp.parseObj = function(isPattern, refDestructuringErrors) {
 
 pp.parseProperty = function(isPattern, refDestructuringErrors) {
   let prop = this.startNode(), isGenerator, isAsync, startPos, startLoc
+  if (this.options.ecmaVersion >= 9 && this.eat(tt.ellipsis)) {
+    if (isPattern) {
+      prop.argument = this.parseIdent(false)
+      if (this.type === tt.comma) {
+        this.raise(this.start, "Comma is not permitted after the rest element")
+      }
+      return this.finishNode(prop, "RestElement")
+    }
+    // To disallow parenthesized identifier via `this.toAssignable()`.
+    if (this.type === tt.parenL && refDestructuringErrors) {
+      if (refDestructuringErrors.parenthesizedAssign < 0) {
+        refDestructuringErrors.parenthesizedAssign = this.start
+      }
+      if (refDestructuringErrors.parenthesizedBind < 0) {
+        refDestructuringErrors.parenthesizedBind = this.start
+      }
+    }
+    // Parse argument.
+    prop.argument = this.parseMaybeAssign(false, refDestructuringErrors)
+    // To disallow trailing comma via `this.toAssignable()`.
+    if (this.type === tt.comma && refDestructuringErrors && refDestructuringErrors.trailingComma < 0) {
+      refDestructuringErrors.trailingComma = this.start
+    }
+    // Finish
+    return this.finishNode(prop, "SpreadElement")
+  }
   if (this.options.ecmaVersion >= 6) {
     prop.method = false
     prop.shorthand = false

src/loose/expression.js

@@ -368,6 +368,12 @@ lp.parseObj = function() {
   if (this.curIndent + 1 < indent) { indent = this.curIndent; line = this.curLineStart }
   while (!this.closes(tt.braceR, indent, line)) {
     let prop = this.startNode(), isGenerator, isAsync, start
+    if (this.options.ecmaVersion >= 9 && this.eat(tt.ellipsis)) {
+      prop.argument = this.parseMaybeAssign()
+      node.properties.push(this.finishNode(prop, "SpreadElement"))
+      this.eat(tt.comma)
+      continue
+    }
     if (this.options.ecmaVersion >= 6) {
       start = this.storeCurrentPos()
       prop.method = false
@@ -476,12 +482,13 @@ lp.toAssignable = function(node, binding) {
     return this.dummyIdent()
   } else if (node.type == "ObjectExpression") {
     node.type = "ObjectPattern"
-    let props = node.properties
-    for (let prop of props)
-      this.toAssignable(prop.value, binding)
+    for (let prop of node.properties)
+      this.toAssignable(prop, binding)
   } else if (node.type == "ArrayExpression") {
     node.type = "ArrayPattern"
     this.toAssignableList(node.elements, binding)
+  } else if (node.type == "Property") {
+    this.toAssignable(node.value, binding)
   } else if (node.type == "SpreadElement") {
     node.type = "RestElement"
     this.toAssignable(node.argument, binding)

src/lval.js

@@ -23,8 +23,20 @@ pp.toAssignable = function(node, isBinding, refDestructuringErrors) {
     case "ObjectExpression":
       node.type = "ObjectPattern"
       if (refDestructuringErrors) this.checkPatternErrors(refDestructuringErrors, true)
-      for (let prop of node.properties)
+      for (let prop of node.properties) {
         this.toAssignable(prop, isBinding)
+        // Early error:
+        //   AssignmentRestProperty[Yield, Await] :
+        //     `...` DestructuringAssignmentTarget[Yield, Await]
+        //
+        //   It is a Syntax Error if |DestructuringAssignmentTarget| is an |ArrayLiteral| or an |ObjectLiteral|.
+        if (
+          prop.type === "RestElement" &&
+          (prop.argument.type === "ArrayPattern" || prop.argument.type === "ObjectPattern")
+        ) {
+          this.raise(prop.argument.start, "Unexpected token")
+        }
+      }
       break
 
     case "Property":

src/statement.js

@@ -665,13 +665,17 @@ pp.checkPatternExport = function(exports, pat) {
     this.checkExport(exports, pat.name, pat.start)
   else if (type == "ObjectPattern")
     for (let prop of pat.properties)
-      this.checkPatternExport(exports, prop.value)
+      this.checkPatternExport(exports, prop)
   else if (type == "ArrayPattern")
     for (let elt of pat.elements) {
       if (elt) this.checkPatternExport(exports, elt)
     }
+  else if (type == "Property")
+    this.checkPatternExport(exports, pat.value)
   else if (type == "AssignmentPattern")
     this.checkPatternExport(exports, pat.left)
+  else if (type == "RestElement")
+    this.checkPatternExport(exports, pat.argument)
   else if (type == "ParenthesizedExpression")
     this.checkPatternExport(exports, pat.expression)
 }

test/run.js

@@ -10,6 +10,7 @@
     require("./tests-trailing-commas-in-func.js");
     require("./tests-template-literal-revision.js");
     require("./tests-directive.js");
+    require("./tests-rest-spread-properties.js");
     acorn = require("../dist/acorn")
     require("../dist/acorn_loose")
   } else {