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