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Enforce required parameters

Written byPhuoc Nguyen
24 Feb, 2021
In ES6, the default value of a parameter is evaluated if the parameter is missing. It allows us to enfore that a given parameter is required.
const required = () => {
throw new Error('Missing parameter');

const getAges = (yearOfBirth = required()) => new Date().getFullYear() - yearOfBirth;
Calling `getAges()` without parameter will throw the exception `Missing parameter`.
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