Compile ES2015 default and rest parameters to ES5. 

Compile ES2015 default and rest parameters to ES5

hzoo

nicolo-ribaudo

jlhwung

existentialism

@babel/plugin-transform-parameters

Object.defineProperty(exports, "__esModule", {

Object.defineProperty(exports, "convertFunctionParams", {

var _helperPluginUtils = require("@babel/helper-plugin-utils");

var _default = (0, _helperPluginUtils.declare)((api, options) => {

  const ignoreFunctionLength = (_api$assumption = api.assumption("ignoreFunctionLength")) != null ? _api$assumption : options.loose;

  const noNewArrows = (_api$assumption2 = api.assumption("noNewArrows")) != null ? _api$assumption2 : true;

        if (path.isArrowFunctionExpression() && path.get("params").some(param => param.isRestElement() || param.isAssignmentPattern())) {

          path.arrowFunctionToExpression({

            allowInsertArrowWithRest: false,

          if (!path.isFunctionExpression()) return;

        const convertedRest = (0, _rest.default)(path);

        const convertedParams = (0, _params.default)(path, ignoreFunctionLength);

        if (convertedRest || convertedParams) {

var _shadowUtils = require("./shadow-utils");

var _shadowUtils = require("./shadow-utils.js");

const buildDefaultParam = _core.template.statement(`

    arguments.length > ARGUMENT_KEY && arguments[ARGUMENT_KEY] !== undefined ?

const buildLooseDefaultParam = _core.template.statement(`

  if (ASSIGNMENT_IDENTIFIER === UNDEFINED) {

    ASSIGNMENT_IDENTIFIER = DEFAULT_VALUE;

const buildLooseDestructuredDefaultParam = _core.template.statement(`

  let ASSIGNMENT_IDENTIFIER = PARAMETER_NAME === UNDEFINED ? DEFAULT_VALUE : PARAMETER_NAME ;

const buildSafeArgumentsAccess = _core.template.statement(`

  let $0 = arguments.length > $1 ? arguments[$1] : undefined;

function convertFunctionParams(path, ignoreFunctionLength, shouldTransformParam, replaceRestElement) {

  const isSimpleParameterList = params.every(param => param.isIdentifier());

  if (isSimpleParameterList) return false;

    (0, _shadowUtils.collectShadowedParamsNames)(param, scope, shadowedParams);

      if (!param.isIdentifier()) param.traverse(_shadowUtils.iifeVisitor, state);

      if (state.needsOuterBinding) break;

  for (let i = 0; i < params.length; i++) {

    if (shouldTransformParam && !shouldTransformParam(i)) {

      replaceRestElement(path, param, transformedRestNodes);

    const paramIsAssignmentPattern = param.isAssignmentPattern();

    if (paramIsAssignmentPattern && (ignoreFunctionLength || _core.types.isMethod(node, {

      const undefinedNode = scope.buildUndefinedNode();

        body.push(buildLooseDefaultParam({

          ASSIGNMENT_IDENTIFIER: _core.types.cloneNode(left.node),

      } else if (left.isObjectPattern() || left.isArrayPattern()) {

        const paramName = scope.generateUidIdentifier();

        body.push(buildLooseDestructuredDefaultParam({

          ASSIGNMENT_IDENTIFIER: left.node,

          PARAMETER_NAME: _core.types.cloneNode(paramName),

    } else if (paramIsAssignmentPattern) {

      if (firstOptionalIndex === null) firstOptionalIndex = i;

      const defNode = buildDefaultParam({

        ARGUMENT_KEY: _core.types.numericLiteral(i)

    } else if (firstOptionalIndex !== null) {

      const defNode = buildSafeArgumentsAccess([param.node, _core.types.numericLiteral(i)]);

    } else if (param.isObjectPattern() || param.isArrayPattern()) {

      const uid = path.scope.generateUidIdentifier("ref");

      uid.typeAnnotation = param.node.typeAnnotation;

      const defNode = _core.types.variableDeclaration("let", [_core.types.variableDeclarator(param.node, uid)]);

      param.replaceWith(_core.types.cloneNode(uid));

      for (const transformedNode of transformedRestNodes) {

const buildRest = _core.template.statement(`

const restIndex = _core.template.expression(`

  (INDEX < OFFSET || ARGUMENTS.length <= INDEX) ? undefined : ARGUMENTS[INDEX]

const restIndexImpure = _core.template.expression(`

  REF = INDEX, (REF < OFFSET || ARGUMENTS.length <= REF) ? undefined : ARGUMENTS[REF]

const restLength = _core.template.expression(`

  ARGUMENTS.length <= OFFSET ? 0 : ARGUMENTS.length - OFFSET

    return path.scope.bindingIdentifierEquals(state.name, state.outerBinding);

const memberExpressionOptimisationVisitor = {

    if (!path.scope.bindingIdentifierEquals(state.name, state.outerBinding)) {

    if (path.isTypeCastExpression()) return;

    const oldNoOptimise = state.noOptimise;

    path.traverse(memberExpressionOptimisationVisitor, state);

    if (!referencesRest(path, state)) return;

      if (parentPath.listKey === "params" && parentPath.key < state.offset) {

      if (parentPath.isMemberExpression({

        const grandparentPath = parentPath.parentPath;

        const argsOptEligible = !state.deopted && !(grandparentPath.isAssignmentExpression() && parentPath.node === grandparentPath.node.left || grandparentPath.isLVal() || grandparentPath.isForXStatement() || grandparentPath.isUpdateExpression() || grandparentPath.isUnaryExpression({

        }) || (grandparentPath.isCallExpression() || grandparentPath.isNewExpression()) && parentPath.node === grandparentPath.node.callee);

          if (parentPath.node.computed) {

            if (parentPath.get("property").isBaseType("number")) {

          } else if (parentPath.node.property.name === "length") {

      if (state.offset === 0 && parentPath.isSpreadElement()) {

        const call = parentPath.parentPath;

        if (call.isCallExpression() && call.node.arguments.length === 1) {

  "name": "@babel/plugin-transform-parameters",

  "description": "Compile ES2015 default and rest parameters to ES5",

    "url": "https://github.com/babel/babel.git",

    "directory": "packages/babel-plugin-transform-parameters"

  "homepage": "https://babel.dev/docs/en/next/babel-plugin-transform-parameters",

    "@babel/helper-plugin-utils": "^7.22.5"

    "@babel/helper-plugin-test-runner": "^7.22.5"

  "author": "The Babel Team (https://babel.dev/team)",

> Compile ES2015 default and rest parameters to ES5

See our website [@babel/plugin-transform-parameters](https://babeljs.io/docs/en/babel-plugin-transform-parameters) for more information.

See our website [@babel/plugin-transform-parameters](https://babeljs.io/docs/babel-plugin-transform-parameters) for more information.

npm install --save-dev @babel/plugin-transform-parameters

yarn add @babel/plugin-transform-parameters --dev

		@@ -14,4 +14,4 @@ "use strict";
		var _helperPluginUtils = require("@babel/helper-plugin-utils");
		var _params = require("./params");
		var _rest = require("./rest");
		var _params = require("./params.js");
		var _rest = require("./rest.js");
		var _default = (0, _helperPluginUtils.declare)((api, options) => {
		@@ -18,0 +18,0 @@ var _api$assumption, _api$assumption2;

		{
		"name": "@babel/plugin-transform-parameters",
		"version": "7.22.5",
		"version": "7.22.15",
		"description": "Compile ES2015 default and rest parameters to ES5",
		@@ -26,3 +26,3 @@ "repository": {
		"devDependencies": {
		"@babel/core": "^7.22.5",
		"@babel/core": "^7.22.15",
		"@babel/helper-plugin-test-runner": "^7.22.5"
		@@ -29,0 +29,0 @@ },

		@@ -8,3 +8,3 @@ "use strict";
		var _core = require("@babel/core");
		var _shadowUtils = require("./shadow-utils");
		var _shadowUtils = require("./shadow-utils.js");
		const buildDefaultParam = _core.template.statement(`
		@@ -11,0 +11,0 @@ let VARIABLE_NAME =

		@@ -5,3 +5,3 @@ # @babel/plugin-transform-parameters

		See our website [@babel/plugin-transform-parameters](https://babeljs.io/docs/en/babel-plugin-transform-parameters) for more information.
		See our website [@babel/plugin-transform-parameters](https://babeljs.io/docs/babel-plugin-transform-parameters) for more information.

		@@ -8,0 +8,0 @@ ## Install

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