Today #Day115 of #365DaysOfCode, Learning 10 Tricky JavaScript Coding Interview Questions
1. Given a string, reverse each word in the sentence
var string = "Welcome to this Javascript Guide!";
// Output becomes !ediuG tpircsavaJ siht ot emocleW
var reverseEntireSentence = reverseBySeparator(string, "");
// Output becomes emocleW ot siht tpircsavaJ !ediuG
var reverseEachWord = reverseBySeparator(reverseEntireSentence, " ");
function reverseBySeparator(string, separator) {
return string.split(separator).reverse().join(separator);
}
Code: reverse [link]
2. How to empty an array in JavaScript?
var arrayList = ['a', 'b', 'c', 'd', 'e', 'f'];
Method 1
arrayList = [];
Method 2
arrayList.length = 0;
Method 3
arrayList.splice(0, arrayList.length);
3. How would you check if a number is an integer?
function isInt(num) {
return num % 1 === 0;
}
console.log(isInt(4)); // true
console.log(isInt(12.2)); // false
console.log(isInt(0.3)); // false
4. Explain what a callback function is and provide a simple example
A callback function is a function that is passed to another function as an argument and is executed after some operation has been completed. Below is an example of a simple callback function that logs to the console after some operations have been completed.
function modifyArray(arr, callback) {
// do something to arr here
arr.push(100);
// then execute the callback function that was passed
callback();
}
var arr = [1, 2, 3, 4, 5];
modifyArray(arr, function() {
console.log("array has been modified", arr);
});
5. Given two strings, return true if they are anagrams of one another
An anagram of a string is another string that contains the same characters, only the order of characters can be different. For example, “abcd” and “dabc” are anagram of each other.
const word1 = "mary",
word2 = "army";
function checkAnagram(w1, w2) {
w1 = w1.split("").sort().join("");
w2 = w2.split("").sort().join("");
console.log(w1, w2);
return w1 === w2;
}
const log = checkAnagram(word1, word2);
console.log(log);
Conclusion
Learned and Practised Tricky JavaScript Coding Interview Questions.
Code
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