Statement Replace Arrow For Free

Arrow functions, introduced in ES6, provides a concise way to write functions in JavaScript. Another significant advantage it offers is the fact that it does not bind its own this. In other words, the context inside arrow functions is lexically or statically defined.

A function expression is very similar to and has almost the same syntax as a function declaration (see function statement for details). The main difference between a function expression and a function declaration is the function name, which can be omitted in function expressions to create anonymous functions.

In a function, in strict mode, this is undefined . In an event, this refers to the element that received the event. Methods like call() , and apply() can refer this to any object.

An arrow function expression is an anonymous function expression written with the fat arrow syntax ( => ). Like traditional function expressions, arrow functions are not hoisted, and so you cannot call them before you declare them. They are also always anonymousthere is no way to name an arrow function.

Unlike regular functions, arrow functions do not have their own this . Arguments objects are not available in arrow functions, but are available in regular functions. Regular functions created using function declarations or expressions are 'constructible' and 'callable'.

If you use arrow functions within render , each call to render will create new function objects. If you then pass these functions to child elements via props , optimizations based on PureComponent or shouldComponentUpdate will fail (as the arrow function props will change on every render).

An arrow function doesn't have its own this value and the arguments object. Therefore, you should not use it as an event handler, a method of an object literal, a prototype method, or when you have a function that uses the arguments object.