freeCodeCamp/guide/english/certifications/javascript-algorithms-and-data-structures/basic-algorithm-scripting/confirm-the-ending/index.md

---
title: Confirm the Ending
---
## Confirm the Ending



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# 🌻 Intermediate Code Solution:
 (Declarative approach)

```javascript
function confirmEnding(str, target) {
  // "Never give up and good luck will find you."
  // -- Falcor
  
  return str.slice(str.length - target.length) === target;
}

confirmEnding("He has to give me a new name", "name");
```

#### 🚀 [Run Code](https://repl.it/repls/SardonicRoundAfkgaming)

# Code Explanation:
 - First we use the `slice` method copy the string.
 - In order to get the last characters in `str` equivalent to the `target`'s length we use the `slice` method.
 - The first parameter inside the `slice` method is the starting index and the second parameter would be the ending index.
 - For example `str.slice(10, 17)` would return `give me`.
 - In this case we only include one parameter which it will copy everything from the starting index.
 - We substract the length of `str` and the length of `target`, that way, we shall get the last remaining characters equivalent to the `target`'s length.
 - Finally we compare the return result of slice to `target` and check if they have the same characters.

### Relevant Links
 - [String.prototype.slice()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/slice)


# ![:rotating_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/rotating_light.png?v=3 ":rotating_light:")Advanced Code Solution:
 (using Regular Expression)
 
 ```javascript
function confirmEnding(str, target) {
  // "Never give up and good luck will find you."
  // -- Falcor
  
  let re = new RegExp(target+'$','i');
  
  return re.test(str);
}

console.log(confirmEnding("Bastian", "n"));
```

## Code Explanation:
 - We need to make a pattern from the `target` variable that exists at the end of the string `str`.
 - Since we will use a variable that will change the pattern each time the function is called, we will use the constructor of the regular expression object `new RegExp(pattern[, flags])`, so we start with: `new RegExp(target)`.
 - Then we have to check at the end of the string, so we concatenate to the `target` variable the `$` character to match the end: `new RegExp(target+'$')`.
 - We use the flag `i` to ignore the case of the pattern and we have our completed RegExp: `new RegExp(target+'$','i')`, or we can ommit the flag entirely.
 - Finally, we are using our regular expression with the `test` method to the given string, to check if the string ends with the pattern and return true or false accordingly.
 
 ### Relevant Links
  - [RegExp](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp)
  - [RegExp.prototype.test()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/test)