[Bug]: rest operator produces global variables

💻

• Would you like to work on a fix?

How are you using Babel?

Programmatic API (babel.transform, babel.parse)

Input code

`export const Event = (function init() { function getsomething(){ let o = { ‘siteIds’:122, ‘sitename’:‘test’, ‘sitecity’: ‘san fran’ }; return o; } const { siteIds, …rest } = getsomething();

return {getsomething}; })();

` reproducible here https://babeljs.io/repl#?browsers=defaults%2C not ie 11%2C not ie_mob 11&build=&builtIns=false&corejs=3.6&spec=false&loose=false&code_lz=KYDwDg9gTgLgBAYwgOwM7wKIDdjPgXjgAoAzAV2QRgEsU5rlqYiBKOAbwChzKa6BzYDFQQAtkIAWDfqy5x5cADZC4EOITkK4AclRNgASQAmqbQC4AjACYrAGk5ademLgCG489pfpt9x7v0EJgBPcydXZDgSKAjtBy0AXwBuePkoITIoSIgUhNTEFHQOOGdDE1s4ADpq9KKE9Xz5QWExSWlWFPl49JhMyPZmkXEYKWR-ZM4Elg6gA&debug=false&forceAllTransforms=true&shippedProposals=false&circleciRepo=&evaluate=true&fileSize=false&timeTravel=false&sourceType=module&lineWrap=true&presets=env%2Ctypescript&prettier=false&targets=&version=7.15.3&externalPlugins=&assumptions={}

In v7.15.3 -> the compiled output creates a global variable called _excluded. in v7.13.17 -> the compiled output does not create a global variable, instead it places the array inline.

Is this expected? is there a way to turn this off and revert to use v7.13.17 behavior?

Multiple scripts will collide with same global variable.

Configuration file name

No response

Configuration

No response

Current and expected behavior

In v7.15.3 -> the compiled output creates a global variable called _excluded. in v7.13.17 -> the compiled output does not create a global variable, instead it places the array inline.

Is this expected? is there a way to turn this off and revert to use v7.13.17 behavior?

Multiple scripts will collide with same global variable.

Environment

see https://babeljs.io/repl#?browsers=defaults%2C not ie 11%2C not ie_mob 11&build=&builtIns=false&corejs=3.6&spec=false&loose=false&code_lz=KYDwDg9gTgLgBAYwgOwM7wKIDdjPgXjgAoAzAV2QRgEsU5rlqYiBKOAbwChzKa6BzYDFQQAtkIAWDfqy5x5cADZC4EOITkK4AclRNgASQAmqbQC4AjACYrAGk5ademLgCG489pfpt9x7v0EJgBPcydXZDgSKAjtBy0AXwBuePkoITIoSIgUhNTEFHQOOGdDE1s4ADpq9KKE9Xz5QWExSWlWFPl49JhMyPZmkXEYKWR-ZM4Elg6gA&debug=false&forceAllTransforms=true&shippedProposals=false&circleciRepo=&evaluate=true&fileSize=false&timeTravel=false&sourceType=module&lineWrap=true&presets=env%2Ctypescript&prettier=false&targets=&version=7.15.3&externalPlugins=&assumptions={}

Possible solution

No response

Additional context

No response

[jakeye-nuvolo]

Thanks for the responses. This issue arises from our setup actually. We are using babel to transpile typescript back to a 3rd party SaaS platform as javascript files. The final destination of the script files are recompiled into basically a single JS file for the sake of this argument.

Are there ways or options to work around this and keep the original behavior of inline placement of the variables?

Appreciate the help and assistance on this matter.

[jakeye-nuvolo]

unexpected output

`“use strict”;

Object.defineProperty(exports, “__esModule”, { value: true }); exports.Event = void 0; var _excluded = [“siteIds”];

function _objectWithoutProperties(source, excluded) { if (source == null) return {}; var target = _objectWithoutPropertiesLoose(source, excluded); var key, i; if (Object.getOwnPropertySymbols) { var sourceSymbolKeys = Object.getOwnPropertySymbols(source); for (i = 0; i < sourceSymbolKeys.length; i++) { key = sourceSymbolKeys[i]; if (excluded.indexOf(key) >= 0) continue; if (!Object.prototype.propertyIsEnumerable.call(source, key)) continue; target[key] = source[key]; } } return target; }

function _objectWithoutPropertiesLoose(source, excluded) { if (source == null) return {}; var target = {}; var sourceKeys = Object.keys(source); var key, i; for (i = 0; i < sourceKeys.length; i++) { key = sourceKeys[i]; if (excluded.indexOf(key) >= 0) continue; target[key] = source[key]; } return target; }

var Event = function init() { function getsomething() { var o = { ‘siteIds’: 122, ‘sitename’: ‘test’, ‘sitecity’: ‘san fran’ }; return o; }

var _getsomething = getsomething(), siteIds = _getsomething.siteIds, rest = _objectWithoutProperties(_getsomething, _excluded);

return { getsomething: getsomething }; }();

exports.Event = Event;`

Expected Output

“use strict”;

Object.defineProperty(exports, “__esModule”, { value: true }); exports.Event = void 0;

function _objectWithoutProperties(source, excluded) { if (source == null) return {}; var target = _objectWithoutPropertiesLoose(source, excluded); var key, i; if (Object.getOwnPropertySymbols) { var sourceSymbolKeys = Object.getOwnPropertySymbols(source); for (i = 0; i < sourceSymbolKeys.length; i++) { key = sourceSymbolKeys[i]; if (excluded.indexOf(key) >= 0) continue; if (!Object.prototype.propertyIsEnumerable.call(source, key)) continue; target[key] = source[key]; } } return target; }

function _objectWithoutPropertiesLoose(source, excluded) { if (source == null) return {}; var target = {}; var sourceKeys = Object.keys(source); var key, i; for (i = 0; i < sourceKeys.length; i++) { key = sourceKeys[i]; if (excluded.indexOf(key) >= 0) continue; target[key] = source[key]; } return target; }

var Event = function init() { function getsomething() { var o = { ‘siteIds’: 122, ‘sitename’: ‘test’, ‘sitecity’: ‘san fran’ }; return o; }

var _getsomething = getsomething(), siteIds = _getsomething.siteIds, rest = _objectWithoutProperties(_getsomething, [“siteIds”]);

return { getsomething: getsomething }; }();

exports.Event = Event;