@thisismanta/pessimist/parseBoolean.js

This is a Node.js library that helps derive `process.argv` into a first-hand-**TypeScript** value-strict object with very minimal configurations.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.parseBoolean = parseBoolean;
const known = Object.fromEntries('false|f|0|n|no|off'.split('|').map(item => [item, false]));
/**
 * Returns a Boolean derived from the given value.
 * @param fallbackValue The value to return if the input is undefined or NaN.
 * @example
 * parseBoolean(undefined) // false
 * parseBoolean(undefined, fallback) // fallback
 * parseBoolean(NaN, fallback) // fallback
 * parseBoolean(null) // false
 * parseBoolean('') // false
 * parseBoolean(0) // false
 * parseBoolean('0') // false
 * parseBoolean('') // false
 * parseBoolean('F') // false
 * parseBoolean('false') // false
 * parseBoolean('n') // false
 * parseBoolean('no') // false
 * parseBoolean('off') // false
 * parseBoolean('otherwise') // true
 */
function parseBoolean(value, fallbackValue = false) {
    if (value === undefined) {
        return fallbackValue;
    }
    if (value === null || value === '') {
        return false;
    }
    if (typeof value === 'boolean') {
        return value;
    }
    if (typeof value === 'number') {
        if (isNaN(value)) {
            return fallbackValue;
        }
        return value !== 0;
    }
    if (typeof value === 'string') {
        return known[value.trim().toLowerCase()] ?? true;
    }
    return true;
}