You seem to be operating under a misconception that there are two objects A and B when you are in the constructor of the derived class B. This is not the case at all. There is one and only one object. Both A and B contribute properties and methods to that one object. The value … Read more
Code-wise, there is no specific disadvantage. JS engines are smart enough to not have performance differences between a string literal and a template literal without variables. In fact, I might even argue that it is good to always use template literals: You can already use single quotes or double quotes to make strings. Choosing which … Read more
Every route has an onEnter hook which is called before the route transition happens. Handle the onEnter hook with a custom requireAuth function. <Route path=”/search” component={Search} onEnter={requireAuth} /> A sample requireAuth is shown below. If the user is authenticated, transition via next(). Else replace the pathname with /login and transition via next(). The login is … Read more
No, you can’t use yield inside of the inner function. But in your case you don’t need it. You can always use for-of loop instead of forEach method. It will look much prettier, and you can use continue, break, yield inside it: var trivialGenerator = function *(array) { for (var item of array) { // … Read more
The next method exists on the generator that the function returns, not on the generator function itself. export default class GeneratorClass { constructor() { const iterator = this.generator(10); iterator.next(); } *generator(count:number): IterableIterator<number> { while(true) yield count++; } }
Since it’s a stateless component it doesn’t have the component lifecycle. Therefor you can’t specify a constructor. You have to extend React.Component to create a stateful component which then will need a constructor and you’ll be able to use the state. Update Since React 16.8.0 and Hooks got introduced there are more options. Hooks are … Read more
You should not use externals: [nodeExternals()], in web app. According to https://github.com/liady/webpack-node-externals it is only for backend. Since you use nodeExternals in web app you get CommonJS modules, that expects built in node require function. So just remove it to fix error.
You can export like this: import App from ‘./App’; import Home from ‘./Home’; import PageWrapper from ‘./PageWrapper’; export { App, Home, PageWrapper } Then, you can import like this wherever you need it: import { App, PageWrapper } from ‘./index’ //or similar filename … You can read more about import and export here. I also … Read more
The points made in this React answer are still valid in Angular, any other framework or vanilla JavaScript/TypeScript. Class prototype methods are ES6, class arrow methods aren’t. Arrow methods belong to class fields proposal and not a part of existing specs. They are implemented in TypeScript and can be transpiled with Babel as well. It’s … Read more
If you want to ensure that the value is not only a function, but really a constructor function for a class, you can convert the function to a string and inspect its representation. The spec dictates the string representation of a class constructor. function isClass(v) { return typeof v === ‘function’ && /^\s*class\s+/.test(v.toString()); } Another … Read more