@fernando.vasquez/either-factory v1.0.1

Either abstraction module

Get Started

Load the module

// Loding the module
const { createLeft, createRight } = require("@fernando.vasquez/either-class");

Instances on Right and Left

// Right object
const right = createRight("foo", { foo: "bar" }]);

// Left object
const left = createLeft("foo", { foo: "bar" }]);

Exmaple

const { createLeft, createRight } = require("@fernando.vasquez/either-class");

const prop = (key, object) =>
  key in object
    ? createRight(object[key])
    : createLeft(`Cannot read property '${key}'`);

const foobar = prop("foo", { foo: "bar" });
const bazbar = prop("baz", { foo: "bar" });

console.log(foobar.map(word => `${word}!`));                              // -> Right("bar!")
console.log(bazbar.map(word => `${word}!`));                              // -> Left("Cannot read property 'baz'")
foobar.runEither(error => console.error(new Error(error)), console.log); // -> foo
bazbar.runEither(error => console.error(new Error(error)), console.log); // -> Error: "Cannot read property 'baz'" at ...
console.log(prop("foo", { foo: "bar" }).getType());                      // -> Either
console.log(prop("baz", { foo: "bar" }).getType());                      // -> Either