JavaScript: Get the nth element of a given array
JavaScript fundamental (ES6 Syntax): Exercise-173 with Solution
Write a JavaScript program to get the nth element of a given array.
- Use Array.prototype.slice() to get an array containing the nth element at the first place.
- If the index is out of bounds, return undefined.
- Omit the second argument, n, to get the first element of the array.
Sample Solution:
JavaScript Code:
//#Source https://bit.ly/2neWfJ2
const nthElement = (arr, n = 0) => (n > 0 ? arr.slice(n, n + 1) : arr.slice(n))[0];
console.log(nthElement(['a', 'b', 'c'], 1));
console.log(nthElement(['a', 'b', 'b'], -3));
Sample Output:
b a
Pictorial Presentation:
Flowchart:

Live Demo:
See the Pen javascript-basic-exercise-173-1 by w3resource (@w3resource) on CodePen.
Improve this sample solution and post your code through Disqus
Previous: Write a JavaScript program to create a function that invokes the provided function with its arguments transformed.
Next: Write a JavaScript program to convert a NodeList to an array.
What is the difficulty level of this exercise?
Test your Programming skills with w3resource's quiz.
JavaScript: Tips of the Day
Checking if a key exists in a JavaScript object?
Checking for undefined-ness is not an accurate way of testing whether a key exists. What if the key exists but the value is actually undefined?
var obj = { key: undefined }; obj["key"] !== undefined // false, but the key exists!
You should instead use the in operator:
"key" in obj // true, regardless of the actual value
If you want to check if a key doesn't exist, remember to use parenthesis:
!("key" in obj) // true if "key" doesn't exist in object !"key" in obj // ERROR! Equivalent to "false in obj"
Or, if you want to particularly test for properties of the object instance (and not inherited properties), use hasOwnProperty:
obj.hasOwnProperty("key") // true
Checking for undefined-ness is not an accurate way of testing whether a key exists. What if the key exists but the value is actually undefined? var obj = { key: undefined }; obj["key"] !== undefined // false, but the key exists! You should instead use the in operator: "key" in obj // true, regardless of the actual value If you want to check if a key doesn't exist, remember to use parenthesis: !("key" in obj) // true if "key" doesn't exist in object !"key" in obj // ERROR! Equivalent to "false in obj" Or, if you want to particularly test for properties of the object instance (and not inherited properties), use hasOwnProperty: obj.hasOwnProperty("key") // true For performance comparison between the methods that are in, hasOwnProperty and key is undefined.
Ref: https://bit.ly/2CFNp1X
- New Content published on w3resource:
- HTML-CSS Practical: Exercises, Practice, Solution
- Java Regular Expression: Exercises, Practice, Solution
- Scala Programming Exercises, Practice, Solution
- Python Itertools exercises
- Python Numpy exercises
- Python GeoPy Package exercises
- Python Pandas exercises
- Python nltk exercises
- Python BeautifulSoup exercises
- Form Template
- Composer - PHP Package Manager
- PHPUnit - PHP Testing
- Laravel - PHP Framework
- Angular - JavaScript Framework
- Vue - JavaScript Framework
- Jest - JavaScript Testing Framework