JS原型链总结：构造函数、实例、原型对象之间的关系

构造函数、实例、原型对象之间的关系

instanceof原理

检测对象的原型对象与构造函数的原型是否是同一个对象，如果不是，根据对象的原型链依次查找，直到相等，或者到达原型链顶端。

上面文字可能表达的不是很清楚，下面上代码：

function myinstanceof (obj, constructor) {
  // 对象的原型对象
  let objproto = object.getprototypeof(obj);
  // 构造函数的原型对象
  let constructorproto = constructor.prototype;

  if (objproto === constructorproto) {
    return true;
  } else {
    while (objproto = object.getprototypeof(objproto)) {
      if (objproto === constructorproto) {
        return true;
      }
    }
    return false;
  }
}

function person (name) {
  this.name = name;
}

person.prototype.hi = function () {
  console.log(`hi, my name is ${this.name}`);
};

let p = new person('monkey');
p.hi();
console.log('------------------------------------------------');
let other = {name: 'lucy'};

console.log(`p is myinstanceof person : ${myinstanceof(p, person)}`);
console.log(`p is myinstanceof object : ${myinstanceof(p, object)}`);
console.log(`other is myinstanceof person : ${myinstanceof(other, person)}`);
console.log(`other is myinstanceof object : ${myinstanceof(other, object)}`);
console.log('------------------------------------------------');
console.log(`p is instanceof person : ${myinstanceof(p, person)}`);
console.log(`p is instanceof object : ${myinstanceof(p, object)}`);
console.log(`other is instanceof person : ${myinstanceof(other, person)}`);
console.log(`other is instanceof object : ${myinstanceof(other, object)}`);

使用myinstanceof和instanceof的结果是一致的