单项选择题 下面代码的输出是什么?（） function Person(firstName, lastName) { this.firstName = firstName; this.lastName = lastName; } const lydia = new Person("Lydia", "Hallie"); const sarah = Person("Sarah", "Smith"); console.log(lydia); console.log(sarah);

单项选择题 下面代码的输出是什么?（） var a = 3; var b = new Number; var c = 3; console.log(a == b); console.log(a === b); console.log(b === c);

单项选择题 下面代码的输出是什么?（） let c = { greeting: "Hey!" }; let d; d = c; c.greeting = "Hello"; console.log(d.greeting);