@babel/plugin-proposal-object-rest-spread outputs verbose code as 7.5.0

[peter-mouland]

Bug Report

Current Behavior
as of 7.5.0 the output of my distributed code has become more verbose. I'm not sure if it's a bug or intended side-effect of another change. If it's intended, I haven't worked out how to reduce the output again.

Basically a single-line babel-helper has been replaced at the top of the file with multi in-line functions

Input Code

const test = { t: 'test' };
const { t } = test;
const foo = (...args) => args;

const a = ['a', 'b', 'c'];
const b = [...a, 'foo'];
const c = foo(...a);

export const es6a = foo;
export const es6b = { ...test, t, a, b, c };

output

import _defineProperty from "@babel/runtime/helpers/defineProperty";

function ownKeys(object, enumerableOnly) { var keys = Object.keys(object); if (Object.getOwnPropertySymbols) { var symbols = Object.getOwnPropertySymbols(object); if (enumerableOnly) symbols = symbols.filter(function (sym) { return Object.getOwnPropertyDescriptor(object, sym).enumerable; }); keys.push.apply(keys, symbols); } return keys; }

function _objectSpread(target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i] != null ? arguments[i] : {}; if (i % 2) { ownKeys(source, true).forEach(function (key) { _defineProperty(target, key, source[key]); }); } else if (Object.getOwnPropertyDescriptors) { Object.defineProperties(target, Object.getOwnPropertyDescriptors(source)); } else { ownKeys(source).forEach(function (key) { Object.defineProperty(target, key, Object.getOwnPropertyDescriptor(source, key)); }); } } return target; }

var test = {
  t: 'test'
};
var t = test.t;

var foo = function foo() {
  for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
    args[_key] = arguments[_key];
  }

  return args;
};

var a = ['a', 'b', 'c'];
var b = [].concat(a, ['foo']);
var c = foo.apply(void 0, a);
export var es6a = foo;
export var es6b = _objectSpread({}, test, {
  t: t,
  a: a,
  b: b,
  c: c
});

Expected behavior/code
previously, 7.4.4, output included a helper and much less code.

output

import _objectSpread from "@babel/runtime/helpers/objectSpread";
var test = {
  t: 'test'
};
var t = test.t;

var foo = function foo() {
  for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
    args[_key] = arguments[_key];
  }

  return args;
};

var a = ['a', 'b', 'c'];
var b = [].concat(a, ['foo']);
var c = foo.apply(void 0, a);
export var es6a = foo;
export var es6b = _objectSpread({}, test, {
  t: t,
  a: a,
  b: b,
  c: c
});

Babel Configuration (.babelrc, package.json, cli command)

module.exports = function babelConfig(api) {
    api.cache(true);

    return {
        presets: [
            [
                require('@babel/preset-env'),
                {
                    modules: false,
                },
            ],
        ],
        plugins: [
            require('@babel/plugin-transform-runtime'),
            require('@babel/plugin-proposal-object-rest-spread'),
        ],
    };
};

Environment

• Babel version(s): 7.6.0
• Node/npm version: v10.16.0
• OS: OSX 10.14.6
• Monorepo: yes, but reproduce-able in 2 files (js + config)
• How you are using Babel: cli for reproducable example (but found change via node api)

Possible Solution
🤔

playing with the browser targets gives a desired output.

targets: {
        browsers: [ 'Chrome >= 61', 'Firefox >= 60', 'Opera >= 48' ],
},

has there been an update to the spec which these browsers no longer support?
is there another plugin or way that i can fill this gap rather than adding this code at the top of the file?

Additional context/Screenshots
none

[babel-bot]

Hey @peter-mouland! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite.

[JLHwung]

It is intended for spec compliance. I notice that some of the helpers is not transformed to helper imports, in this case one may specify a helper version to transform-runtime. See #10261 (comment).

[JLHwung]

Close as it duplicates #10261