javascript typeError：無法讀取undefined屬性

Question

我試圖在Javascript中創建一個堆棧類，但是我不斷收到上述錯誤的變體。我知道它是構造函數，但我無法找到問題所在。這裏是我的類：

"use strict" 
 

 
class Stack { 
 
    constuctor() { 
 
     this.items = []; 
 
    } 
 

 
    emptyArray() { 
 
     if (this.items === 0) { 
 
      this.error = "The stack is empty"; 
 
     } 
 
     return this.error; 
 
    } 
 

 
    isEmpty() { 
 
     return this.items === 0; 
 
    } 
 

 
    push(x) { 
 
     return this.items.push(x); 
 
    } 
 

 
    pop() { 
 
     if (this.items >= 1) { 
 
      return this.items.pop(); 
 
     } 
 
     else { 
 
      throw new emptyArray(); 
 
     } 
 
    } 
 

 
    size() { 
 
     return this.items.length; 
 
    } 
 

 
    peak() { 
 
     let el1 = this.items.pop(); 
 
     let el2 = this.items.pop(); 
 
     this.items.push(el2); 
 
     this.items.push(el1); 
 
     return el2; 
 
    } 
 
} 
 

 
new Stack().size();

Answer 1

constructor拼寫錯誤：

constuctor() { 
    this.items = []; 
}