JavaScript封装检测数据类型功能、Object、prototype、toString、call

function isType(type) { return function (obj) { return Object.prototype.toString.call(obj) === `[object ${type}]`; } } let isString = isType('String'), isNumber = isType('String'), isObject = isType('Object'); console.log(isString(1)); // false console.log(isString('7')); // true console.log(isNumber(3)); // false console.log(isObject({ id: 1 })); // true