Add support for ES2025 Import Attributes

FEATURE: Support ES2025 import attributes.

Closes #1289

Author: ota-meshi

acorn-loose/src/expression.js

@@ -352,7 +352,9 @@ lp.parseExprImport = function() {
 }
 
 lp.parseDynamicImport = function(node) {
-  node.source = this.parseExprList(tt.parenR)[0] || this.dummyString()
+  const list = this.parseExprList(tt.parenR)
+  node.source = list[0] || this.dummyString()
+  node.options = list[1] || null
   return this.finishNode(node, "ImportExpression")
 }
 

acorn-loose/src/statement.js

@@ -461,6 +461,8 @@ lp.parseExport = function() {
       }
     }
     node.source = this.eatContextual("from") ? this.parseExprAtom() : this.dummyString()
+    if (this.options.ecmaVersion >= 16)
+      node.attributes = this.parseWithClause()
     this.semicolon()
     return this.finishNode(node, "ExportAllDeclaration")
   }
@@ -488,6 +490,8 @@ lp.parseExport = function() {
     node.declaration = null
     node.specifiers = this.parseExportSpecifierList()
     node.source = this.eatContextual("from") ? this.parseExprAtom() : null
+    if (this.options.ecmaVersion >= 16)
+      node.attributes = this.parseWithClause()
     this.semicolon()
   }
   return this.finishNode(node, "ExportNamedDeclaration")
@@ -511,6 +515,8 @@ lp.parseImport = function() {
     node.source = this.eatContextual("from") && this.tok.type === tt.string ? this.parseExprAtom() : this.dummyString()
     if (elt) node.specifiers.unshift(elt)
   }
+  if (this.options.ecmaVersion >= 16)
+    node.attributes = this.parseWithClause()
   this.semicolon()
   return this.finishNode(node, "ImportDeclaration")
 }
@@ -548,6 +554,37 @@ lp.parseImportSpecifiers = function() {
   return elts
 }
 
+lp.parseWithClause = function() {
+  let nodes = []
+  if (!this.eat(tt._with)) {
+    return nodes
+  }
+
+  let indent = this.curIndent, line = this.curLineStart, continuedLine = this.nextLineStart
+  this.pushCx()
+  this.eat(tt.braceL)
+  if (this.curLineStart > continuedLine) continuedLine = this.curLineStart
+  while (!this.closes(tt.braceR, indent + (this.curLineStart <= continuedLine ? 1 : 0), line)) {
+    const attr = this.startNode()
+    attr.key = this.tok.type === tt.string ? this.parseExprAtom() : this.parseIdent()
+    if (this.eat(tt.colon)) {
+      if (this.tok.type === tt.string)
+        attr.value = this.parseExprAtom()
+      else attr.value = this.dummyString()
+    } else {
+      if (isDummy(attr.key)) break
+      if (this.tok.type === tt.string)
+        attr.value = this.parseExprAtom()
+      else break
+    }
+    nodes.push(this.finishNode(attr, "ImportAttribute"))
+    this.eat(tt.comma)
+  }
+  this.eat(tt.braceR)
+  this.popCx()
+  return nodes
+}
+
 lp.parseExportSpecifierList = function() {
   let elts = []
   let indent = this.curIndent, line = this.curLineStart, continuedLine = this.nextLineStart

acorn-walk/src/index.js

@@ -347,19 +347,30 @@ base.ExportNamedDeclaration = base.ExportDefaultDeclaration = (node, st, c) => {
   if (node.declaration)
     c(node.declaration, st, node.type === "ExportNamedDeclaration" || node.declaration.id ? "Statement" : "Expression")
   if (node.source) c(node.source, st, "Expression")
+  if (node.attributes)
+    for (let attr of node.attributes)
+      c(attr, st)
 }
 base.ExportAllDeclaration = (node, st, c) => {
   if (node.exported)
     c(node.exported, st)
   c(node.source, st, "Expression")
+  for (let attr of node.attributes)
+    c(attr, st)
+}
+base.ImportAttribute = (node, st, c) => {
+  c(node.value, st, "Expression")
 }
 base.ImportDeclaration = (node, st, c) => {
   for (let spec of node.specifiers)
     c(spec, st)
   c(node.source, st, "Expression")
+  for (let attr of node.attributes)
+    c(attr, st)
 }
 base.ImportExpression = (node, st, c) => {
   c(node.source, st, "Expression")
+  if (node.options) c(node.options, st, "Expression")
 }
 base.ImportSpecifier = base.ImportDefaultSpecifier = base.ImportNamespaceSpecifier = base.Identifier = base.PrivateIdentifier = base.Literal = ignore
 

acorn/src/acorn.d.ts

@@ -403,6 +403,7 @@ export interface ImportDeclaration extends Node {
   type: "ImportDeclaration"
   specifiers: Array<ImportSpecifier | ImportDefaultSpecifier | ImportNamespaceSpecifier>
   source: Literal
+  attributes: Array<ImportAttribute>
 }
 
 export interface ImportSpecifier extends Node {
@@ -421,11 +422,18 @@ export interface ImportNamespaceSpecifier extends Node {
   local: Identifier
 }
 
+export interface ImportAttribute extends Node {
+  type: "ImportAttribute"
+  key: Identifier | Literal
+  value: Literal
+}
+
 export interface ExportNamedDeclaration extends Node {
   type: "ExportNamedDeclaration"
   declaration?: Declaration | null
   specifiers: Array<ExportSpecifier>
   source?: Literal | null
+  attributes: Array<ImportAttribute>
 }
 
 export interface ExportSpecifier extends Node {
@@ -454,6 +462,7 @@ export interface ExportAllDeclaration extends Node {
   type: "ExportAllDeclaration"
   source: Literal
   exported?: Identifier | Literal | null
+  attributes: Array<ImportAttribute>
 }
 
 export interface AwaitExpression extends Node {
@@ -469,6 +478,7 @@ export interface ChainExpression extends Node {
 export interface ImportExpression extends Node {
   type: "ImportExpression"
   source: Expression
+  options: Expression | null
 }
 
 export interface ParenthesizedExpression extends Node {
@@ -562,7 +572,7 @@ export type ModuleDeclaration =
 | ExportDefaultDeclaration
 | ExportAllDeclaration
 
-export type AnyNode = Statement | Expression | Declaration | ModuleDeclaration | Literal | Program | SwitchCase | CatchClause | Property | Super | SpreadElement | TemplateElement | AssignmentProperty | ObjectPattern | ArrayPattern | RestElement | AssignmentPattern | ClassBody | MethodDefinition | MetaProperty | ImportSpecifier | ImportDefaultSpecifier | ImportNamespaceSpecifier | ExportSpecifier | AnonymousFunctionDeclaration | AnonymousClassDeclaration | PropertyDefinition | PrivateIdentifier | StaticBlock | VariableDeclarator
+export type AnyNode = Statement | Expression | Declaration | ModuleDeclaration | Literal | Program | SwitchCase | CatchClause | Property | Super | SpreadElement | TemplateElement | AssignmentProperty | ObjectPattern | ArrayPattern | RestElement | AssignmentPattern | ClassBody | MethodDefinition | MetaProperty | ImportAttribute | ImportSpecifier | ImportDefaultSpecifier | ImportNamespaceSpecifier | ExportSpecifier | AnonymousFunctionDeclaration | AnonymousClassDeclaration | PropertyDefinition | PrivateIdentifier | StaticBlock | VariableDeclarator
 
 export function parse(input: string, options: Options): Program
 

acorn/src/expression.js

@@ -546,13 +546,32 @@ pp.parseDynamicImport = function(node) {
   // Parse node.source.
   node.source = this.parseMaybeAssign()
 
-  // Verify ending.
-  if (!this.eat(tt.parenR)) {
-    const errorPos = this.start
-    if (this.eat(tt.comma) && this.eat(tt.parenR)) {
-      this.raiseRecoverable(errorPos, "Trailing comma is not allowed in import()")
+  if (this.options.ecmaVersion >= 16) {
+    if (!this.eat(tt.parenR)) {
+      this.expect(tt.comma)
+      if (!this.afterTrailingComma(tt.parenR)) {
+        node.options = this.parseMaybeAssign()
+        if (!this.eat(tt.parenR)) {
+          this.expect(tt.comma)
+          if (!this.afterTrailingComma(tt.parenR)) {
+            this.unexpected()
+          }
+        }
+      } else {
+        node.options = null
+      }
     } else {
-      this.unexpected(errorPos)
+      node.options = null
+    }
+  } else {
+    // Verify ending.
+    if (!this.eat(tt.parenR)) {
+      const errorPos = this.start
+      if (this.eat(tt.comma) && this.eat(tt.parenR)) {
+        this.raiseRecoverable(errorPos, "Trailing comma is not allowed in import()")
+      } else {
+        this.unexpected(errorPos)
+      }
     }
   }
 

acorn/src/statement.js

@@ -859,6 +859,8 @@ pp.parseExportAllDeclaration = function(node, exports) {
   this.expectContextual("from")
   if (this.type !== tt.string) this.unexpected()
   node.source = this.parseExprAtom()
+  if (this.options.ecmaVersion >= 16)
+    node.attributes = this.parseWithClause()
   this.semicolon()
   return this.finishNode(node, "ExportAllDeclaration")
 }
@@ -889,6 +891,8 @@ pp.parseExport = function(node, exports) {
     if (this.eatContextual("from")) {
       if (this.type !== tt.string) this.unexpected()
       node.source = this.parseExprAtom()
+      if (this.options.ecmaVersion >= 16)
+        node.attributes = this.parseWithClause()
     } else {
       for (let spec of node.specifiers) {
         // check for keywords used as local names
@@ -1017,6 +1021,8 @@ pp.parseImport = function(node) {
     this.expectContextual("from")
     node.source = this.type === tt.string ? this.parseExprAtom() : this.unexpected()
   }
+  if (this.options.ecmaVersion >= 16)
+    node.attributes = this.parseWithClause()
   this.semicolon()
   return this.finishNode(node, "ImportDeclaration")
 }
@@ -1077,6 +1083,41 @@ pp.parseImportSpecifiers = function() {
   return nodes
 }
 
+pp.parseWithClause = function() {
+  let nodes = []
+  if (!this.eat(tt._with)) {
+    return nodes
+  }
+  this.expect(tt.braceL)
+  const attributeKeys = {}
+  let first = true
+  while (!this.eat(tt.braceR)) {
+    if (!first) {
+      this.expect(tt.comma)
+      if (this.afterTrailingComma(tt.braceR)) break
+    } else first = false
+
+    const attr = this.parseImportAttribute()
+    const keyName = attr.key.type === "Identifier" ? attr.key.name : attr.key.value
+    if (hasOwn(attributeKeys, keyName))
+      this.raiseRecoverable(attr.key.start, "Duplicate attribute key '" + keyName + "'")
+    attributeKeys[keyName] = true
+    nodes.push(attr)
+  }
+  return nodes
+}
+
+pp.parseImportAttribute = function() {
+  const node = this.startNode()
+  node.key = this.type === tt.string ? this.parseExprAtom() : this.parseIdent(this.options.allowReserved !== "never")
+  this.expect(tt.colon)
+  if (this.type !== tt.string) {
+    this.unexpected()
+  }
+  node.value = this.parseExprAtom()
+  return this.finishNode(node, "ImportAttribute")
+}
+
 pp.parseModuleExportName = function() {
   if (this.options.ecmaVersion >= 13 && this.type === tt.string) {
     const stringLiteral = this.parseLiteral(this.value)

bin/test262.unsupported-features

@@ -1,5 +1,4 @@
 decorators
 explicit-resource-management
 regexp-modifiers
-import-attributes
 source-phase-imports

bin/test262.whitelist

@@ -26,3 +26,7 @@ built-ins/RegExp/property-escapes/generated/Script_Extensions_-_Todhri.js (defau
 built-ins/RegExp/property-escapes/generated/Script_Extensions_-_Todhri.js (strict mode)
 built-ins/RegExp/property-escapes/generated/Script_Extensions_-_Tulu_Tigalari.js (default)
 built-ins/RegExp/property-escapes/generated/Script_Extensions_-_Tulu_Tigalari.js (strict mode)
+language/import/import-attributes/json-invalid.js (default)
+language/import/import-attributes/json-invalid.js (strict mode)
+language/import/import-attributes/json-named-bindings.js (default)
+language/import/import-attributes/json-named-bindings.js (strict mode)

test/run.js

@@ -28,6 +28,7 @@
   require("./tests-numeric-separators.js");
   require("./tests-class-features-2022.js");
   require("./tests-module-string-names.js");
+  require("./tests-import-attributes.js");
   var acorn = require("../acorn")
   var acorn_loose = require("../acorn-loose")