When you use the function body version of an arrow function (with {}), there is no implied return. You have to specify it. When you use the concise body (no {}), the result of the body expression is implicitly returned by the function. So you would write that either with an explicit return: const f … Read more
That is a curried function First, examine this function with two parameters … const add = (x, y) => x + y add(2, 3) //=> 5 Here it is again in curried form … const add = x => y => x + y Here is the same1 code without arrow functions … const add … Read more
A while ago our team migrated all its code (a mid-sized AngularJS app) to JavaScript compiled using Traceur Babel. I’m now using the following rule of thumb for functions in ES6 and beyond: Use function in the global scope and for Object.prototype properties. Use class for object constructors. Use => everywhere else. Why use arrow … Read more
Arrow functions capture the this value of the enclosing context function Person(){ this.age = 0; setInterval(() => { this.age++; // |this| properly refers to the person object }, 1000); } var p = new Person(); So, to directly answer your question, this inside your arrow function would have the same value as it did right … Read more
You must wrap the returning object literal into parentheses. Otherwise curly braces will be considered to denote the function’s body. The following works: p => ({ foo: ‘bar’ }); You don’t need to wrap any other expression into parentheses: p => 10; p => ‘foo’; p => true; p => [1,2,3]; p => null; p … Read more
Jackson has partially answered this in a similar question: Implicit return, but only if there is no block. This will result in errors when a one-liner expands to multiple lines and the programmer forgets to add a return. Implicit return is syntactically ambiguous. (name) => {id: name}returns the object {id: name}… right? Wrong. It returns … Read more
What It Is This is an arrow function. Arrow functions are a short syntax, introduced by ECMAscript 6, that can be used similarly to the way you would use function expressions. In other words, you can often use them in place of expressions like function (foo) {…}. But they have some important differences. For example, … Read more
tl;dr: No! Arrow functions and function declarations / expressions are not equivalent and cannot be replaced blindly. If the function you want to replace does not use this, arguments and is not called with new, then yes. As so often: it depends. Arrow functions have different behavior than function declarations / expressions, so let’s have … Read more