无法调用在javascript中的对象内部定义的方法

Question

i have defined an object containing an array of objects and functions and called the methods as below:

 var Person = { people: [{ name: "Max", age: 41, }, { name: "John", age: 25, }, { name: "Doe", age: 67, }, ], greeting: function() { return "Hello, my name is" + " " + this.name; } }; function searchByName(namePerson) { var result = Person.people.find(Obj => Obj.name === namePerson); return result; } var max = searchByName('Max'); max.greeting(); 

Is something wrong with my function definition? On running it says "greeting" is not a function.

Answer 1

Your code doesn't make much sense, your greeting function is on the outer Person object but you are using it as if it were a property of each person inside the array.

You need a constructor for persons so you can instantiate three Person s with a greeting method

 function Person(name, age) { this.name = name; this.age = age; } Person.prototype.greeting = function() { return "Hello, my name is " + this.name + " and I am " + this.age + " years old"; } const people = [ new Person("Max", 41), new Person("JOhn", 25), new Person("Doe", 67), ]; function searchByName(namePerson) { var result = people.find(obj => obj.name === namePerson); return result; } var max = searchByName('Max'); console.log(max.greeting()); 

Answer 2

You could change your Person into an actual class that you could instantiate with new Person()

 //make the person class function Person ( person ) { this.name = person.name; this.age = person.age; } //add the greeting method to the person class Person.prototype.greeting = function () { return "Hello, my name is" + " " + this.name; }; //build your people var people = [ new Person( { name: "Max", age: 41 } ), new Person( { name: "John", age: 25 } ), new Person( { name: "Doe", age: 67 } ) ]; function searchByName(namePerson) { var result = people.find(person => person.name === namePerson); return result; } var max = searchByName('Max'); console.log( max.greeting() ); 

Answer 3

You're returning an object, which does not have a greeting function.

A potential different solution with a little bit of a different structure is this.

 function Person(name, age) { this.name = name; this.age = age; } Person.prototype.greeting = function() { return "Hello, my name is " + this.name; } function People(personArr) { this.people = personArr; } People.prototype.searchByName = function(name) { return this.people.find( person => person.name === name); } var people = new People([new Person("Max", 41), new Person("John", 25), new Person("Doe", 67)]); var max = people.searchByName("Max"); console.log(max.greeting());