Left file: appwork-v1_3_1/vue-starter/babel.config.js  
Right file: appwork-v1_4_0/vue-starter/babel.config.js  

module.exports = {	=	module.exports = {
presets: [		presets: [
['@vue/app', {	<>	['@vue/cli-plugin-babel/preset', {
polyfills: [	=	polyfills: [
'es6.array.fill',	<>	'es.array.fill',
'es6.array.iterator',		'es.array.iterator',
'es6.object.assign',		'es.object.assign',
'es6.object.keys',		'es.object.keys',
'es6.promise',		'es.promise',
'es6.string.includes',		'es.string.includes',
'es6.symbol',		'es.symbol',
'es7.array.includes',		'es.array.includes',
'es7.object.entries',		'es.object.entries',
'es7.promise.finally',		'es.promise.finally',
'es7.symbol.async-iterator'		'es.symbol.async-iterator'
],	=	],
corejs: 2	<>	corejs: 3
}]	=	}]
]		]
}		}