@yobta/validator/lib/boolean/boolean.js

Tree-shakable es6 validator

import { rule } from '../rule/rule.js';
const truthySet = new Set(['1', 'true', 'yes']);
const falsySet = new Set(['0', 'false', 'no', 'null']);
export const booleanMessage = 'It should be a boolean';
export const boolean = (message = booleanMessage) => rule((input = '') => {
    if (input === '') {
        return undefined;
    }
    const lowerCasedInput = String(input).toLowerCase();
    if (falsySet.has(lowerCasedInput)) {
        return false;
    }
    else if (truthySet.has(lowerCasedInput)) {
        return true;
    }
    throw new Error(message);
});