Book Review: Front-End Reactive Architectures: Explore the Future of the Front-End Using Reactive JavaScript Frameworks and Libraries

(2 / 5)

I had high expectations, but this book doesn’t really cover the topic in depth, its more or less a list of reactive libraries and frameworks. If you want to learn more about the topic its probably better to read related papers, or what’s the talks about RX on youtube.

Pseudomandatory parameters in es6 functions

In many programming languages, the parameters of a function are by default mandatory and the developer has to explicitly define that a parameter is optional. In Javascript, every parameter is optional, but we can enforce this behavior without messing with the actual body of a function, taking advantage of es6’s feature of default values for parameters.

const _err = function(message) {
  throw new Error(message);
}

const getSum = (a = _err('a is not defined'), b = _err('b is not defined')) => a + b;

getSum(10); // throws Error b is not defined

`_err` is a function that immediately throws an Error. If no value is passed for one of the parameters, the default value is going to be used, `err` will be called and an Error will be thrown. You can see more examples for the default parameters feature on Mozilla’s Developer Network.