'use strict'; var boolToStr = Boolean.prototype.toString; var tryBooleanObject = function booleanBrandCheck(value) { try { boolToStr.call(value); return true; } catch (e) { return false; } }; var toStr = Object.prototype.toString; var boolClass = '[object Boolean]'; var hasToStringTag = typeof Symbol === 'function' && typeof Symbol.toStringTag === 'symbol'; module.exports = function isBoolean(value) { if (typeof value === 'boolean') { return true; } if (value === null || typeof value !== 'object') { return false; } return hasToStringTag && Symbol.toStringTag in value ? tryBooleanObject(value) : toStr.call(value) === boolClass; };