@jil/args/src/utils/castValue.ts

A convention based argument parsing and formatting library, with strict validation checks

import {DEFAULT_NUMBER_VALUE} from '../constants';
import {ValueType} from '../types';

export function castValue(value: unknown, type?: 'boolean' | 'number' | 'string', multiple?: boolean): ValueType {
  if (multiple && !Array.isArray(value)) {
    return [];
  }

  if (Array.isArray(value)) {
    return value.map(val => castValue(val, type)) as string[];
  }

  switch (type) {
    case 'boolean': {
      const bool = String(value).toLowerCase();

      return bool === 'true' || bool === 'on' || bool === 'yes' || bool === '1';
    }

    case 'number': {
      const number = Number(value);

      return Number.isNaN(number) ? DEFAULT_NUMBER_VALUE : number;
    }

    default:
      return String(value);
  }
}