ES6 Proxy - ProxyModule

main.js

import SampleModule from './SampleModule';

let sample = new SampleModule();
console.log(sample.a);    // public
console.log(sampple._a);  // Uncaught TypeError: _a is private valiable

SampleModule.js

class SampleModule {
    constructor() {
        this._a = 'private';
        this.a = 'public';
    }
}

const handler = {
    construct(target, args) {
        return new Proxy(Reflect.construct(target, args), handler);
    },
    get(obj, prop) {
        if (prop.indexOf('_') === 0) {
            throw TypeError(`${prop} is private valiable`);
        } else {
            Reflect.get(obj, prop);
        }
    }
}

export default new Proxy(Sample, handler);