Today #Day120 of #365DaysOfCode, Learning Essential JavaScript Interview Questions.

7. In what order will the numbers 1-4 be logged to the console when the code below is executed? Why?

(function() {
    console.log(1); 
    setTimeout(function(){console.log(2)}, 1000); 
    setTimeout(function(){console.log(3)}, 0); 
    console.log(4);
})();

The values will be logged in the following order:

1
4
3
2

The answer has to do with properly understanding JavaScript events and timing.

8. Write a simple function (less than 160 characters) that returns a boolean indicating whether or not a string is a palindrome.

The following one line function will return true if str is a palindrome; otherwise, it returns false.

function isPalindrome(str){
    str = str.replace(/\W/g,'').toLowerCase()
    console.log(str);
    console.log(str.split('a'));
    console.log(str.split('').reverse());
    console.log(str.split('').reverse().join(''));
    return str === str.split('').reverse().join('')
}
console.log(isPalindrome('A car, a man, a maraca'))

For example:

console.log(isPalindrome("level"));                   // logs 'true'
console.log(isPalindrome("levels"));                  // logs 'false'
console.log(isPalindrome("A car, a man, a maraca"));  // logs 'true'

Conclusion

Learned and practiced Essential JavaScript Interview Questions involving topics like setTimeout and Palindrome.

Code

1. code

   

Source: JavaScript Interview Questions [Link]

Author: Dheeraj.y

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