写gulp遇到的ES6问题详解

events.js:182
 throw er; // Unhandled 'error' event
 ^
GulpUglifyError: unable to minify JavaScript

gulp.task('miniJS', function(){
		 gulp.src(['demo.js', 'demo2.js'])
		 	.pipe(concat('demoFile.js'))
			.pipe(babel())
			.pipe(gulp.dest('./finalFile/'))
})

# Babel 7
$ npm install --save-dev gulp-babel @babel/core @babel/preset-env

# Babel 6
$ npm install --save-dev gulp-babel@7 babel-core babel-preset-env

"@babel/core": "^7.1.6",
 "gulp-babel": "^8.0.0",
"@babel/preset-env": "^7.1.6",

.pipe(babel({ 
   presets: ['@babel/env']  
  }))

function demoFunc(){
 //something
}
export demoFunc;

export function demo(){
	console.log('this is the first gulp demo');
}
 export var num = {};

.pipe(babel({
	presets: ['@babel/env']
}))
.pipe(uglify())
.pipe(gulp.dest('file'))