Javascript object prototype function

Question

我在对象中有三种方法。

其中2个工作正常，当第三个打印 - 它打印出代码本身，而不是功能。下面是代码和它的外观在控制台：

function Students(name, lastname, grades){ 
 
    this.name = name; 
 
    this.lastname = lastname; 
 
    this.grades = grades; 
 
    this.addGrade = function(a){ 
 
     this.grades.push(a); 
 
    } 
 
    this.printData = function(){ 
 
     console.log("Name: " + this.name); 
 
     console.log("Grades: " + this.grades); 
 
     console.log("Average: " + this.gradeAvg); 
 
    } 
 
    this.gradeAvg = function(){ 
 
     console.log("blabla"); 
 
    } 
 
} 
 

 
var StudentasA = new Students("Petras", "Petrauskas", [8, 9, 9, 8, 7]); 
 
var StudentasB = new Students("Jurgis", "Jurgauskas", [6, 7, 5, 4, 9]); 
 
StudentasA.printData(); 
 
StudentasA.addGrade(28); 
 
StudentasA.printData();

控制台：

console view

Answer 1

你需要调用函数

this.gradeAvg() 
//   ^^ 

function Students(name, lastname, grades){ 
 
    this.name = name; 
 
    this.lastname = lastname; 
 
    this.grades = grades; 
 
    this.addGrade = function(a){ 
 
     this.grades.push(a); 
 
    } 
 
    this.printData = function(){ 
 
     console.log("Name: " + this.name); 
 
     console.log("Grades: " + this.grades); 
 
     console.log("Average: " + this.gradeAvg()); 
 
     //          ^^ 
 
    } 
 
    this.gradeAvg = function(){ 
 
     return this.grades.reduce(function (a, b) { return a + b; })/this.grades.length; 
 
    } 
 
} 
 

 
var StudentasA = new Students("Petras", "Petrauskas", [8, 9, 9, 8, 7]); 
 
var StudentasB = new Students("Jurgis", "Jurgauskas", [6, 7, 5, 4, 9]); 
 
StudentasA.printData(); 
 
StudentasA.addGrade(28); 
 
StudentasA.printData();

Answer 2

您的代码实际上从未调用该函数。

而是将函数本身直接连接到字符串中。

你想要圆括号。