nick-offerman/lib/index.js

You know how you always have optional values.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.of = exports.Of = void 0;
/** Given a single-parameter constructor, return a function that will accept either
 * null, undefined or that single parameter, and return either null, undefined or a
 * new instance of the corresponding class.
 * @param Ctor the constructor
 * @return an optional factory method
 */
const Of = (Ctor) => (param) => (param == null ? param : new Ctor(param));
exports.Of = Of;
/** Given a function, return a new function with the same shape but an optional first
 * parameter, that returns either null or undefined if that first parameter is
 * null or undefined, or else the result of invoking the wrapped function.
 * @param func the function to wrap
 * @return a new more optional function
 */
const of = (func) => (param, ...rest) => (param == null ? param : func(param, ...rest));
exports.of = of;