使用Substring（）和Substr（）來處理兩個字符串並且Substr（）

Question

可以說我們必須使用Substring（）和/或Substr（）或兩個字符串方法來對字符串var first = "hi my name is this";和var second = "this";進行處理，我想檢查第二個字符串是否匹配首先結束（我知道String.prototype.endsWith（））。這怎麼能做到？感謝

到目前爲止，我有這個，但它的錯誤

function confirmEnding(str, target) { 
    // calculate the length of second string 
    // remove the end of the first string (same amount) with the first string 
    //compare the two 
    var secondStringLen = target.length; 
    var firstStringLen = str.length; 
    var firstStringEnding = str.substring(secondStringLen+1, -1); 

    return firstStringEnding; 
} 

confirmEnding("abcaqwexefg", "efg"); 

Answer 1

你可以試試這個樣子！

var first = "hi my name is this"; 
 
var second = "this"; 
 

 
function confirmEnding(str1, str2) { 
 
    var l1 = str1.length, 
 
    l2 = str2.length; 
 

 
    var str = str1.substring(l1 - l2); 
 

 
    if (str == str2) 
 
    return true; 
 
    else 
 
    return false; 
 
} 
 

 
console.log(confirmEnding("abcaqwexefg", "efg")); 
 
console.log(confirmEnding(first, second));