Mocha has support for ESM from version 7.1.0 onward (release: Feb. 26, 2020). This requires Node 12.11.0 or higher, and is subject to the current restrictions/limitations of using modules in Node: Either you must use .mjs file extensions for source files that use ES modules, or you must have “type”: “module” in your package.json You … Read more
Please upgrade the babel-eslint package to version 10.0.3. This will most likely fix those false-positives where vars are used inside loops and wrongly reported as unused.
You can still attach a method on a class’ prototype; after-all, classes are just syntactic sugar over a “functional object”, which is the old way of using a function to construct objects. Since you want to use ES6, I’ll use an ES6 import. Minimal effort, using the prototype: import getColor from ‘path/to/module’; class Car { … Read more
The language reference uses abstract terms because JavaScript environments can vary widely. In the browser, a window (a frame, a window opened with window.open(), or just a plain browser tab) is a realm. A web worker is a different kind of realm than a window, but it’s a realm. Same goes for service workers. It’s … Read more
As far as I can see, strict refers to the [[Strict]] internal slot of the function object. No. And yes. It does refer to the strictness of the function (or script) in which the block that contains the function declaration occurs. Not to the strictness of the function that is (or is not) to be … Read more
Your solution is fine, though it’ll be better to create all those methods once on a prototype level: [‘GET’, ‘PUT’, ‘POST’, ‘DEL’].forEach((method) => { Executor.prototype[method] = function (body) { return this.request(method, body) } }) prototype approach is slightly faster, because this code is executed only once, while constructor code is executed every time new instance … Read more
Your first example does not actually output a string to the console. Notice how properties is passed as a separate parameter argument (as it is surrounded by commas , and not string-concatenation operators +). When you pass an object (or any JavaScript value) to console as a discrete argument it can display it how it … Read more
I do not understand why it is necessary to have the async keyword before the function keyword. For the same reason that we have the * symbol before generator functions: They mark the function as extraordinary. They are quite similar in that regard – they add a visual marker that the body of this function … Read more
From: http://ejohn.org/blog/ecmascript-5-objects-and-properties/ Writable: If false, the value of the property can not be changed. Configurable: If false, any attempts to delete the property or change its attributes (Writable, Configurable, or Enumerable) will fail. Enumerable: If true, the property will be iterated over when a user does for (var prop in obj){} (or similar).
No. Those parentheses produce an object literal. Arrow functions have many syntaxes, one of which is: ( … ) => expression This will implicitly return an expression, for example: () => 1 + 1 This function will implicitly return 1 + 1, which is 2. Another one is this: ( … ) => { … … Read more