JS Coding Question 8: Capitalize All Words In A Sentence [Not So Easy]

Interview Question #8:

Write a function that will capitalize all words in a sentence.

If you need practice, try to solve this on your own. I have included 3 potential solutions below.

Note: There are many other potential solutions to this problem.

Feel free to bookmark even if you don't need this for now. You may need to refresh/review down the road when it is time for you to look for a new role.

Codepen: If you want to play around and experiment with the code: https://codepen.io/angelo_jin/pen/xxrdBVE

Solution #1: Array Map (Recommended)

• This is one solution I would go by if I am going to be asked in an interview. It pretty straight-forward approach and is legible.

function capitalize(str) {    return str        .split(' ')        .map(word => word[0].toUpperCase() + word.slice(1)).join(' ');}

Solution #2: Array Reduce (Recommended)

• Another solution that I like. Array reduce is used as intended where one value is returned as a result of every iteration. Pretty sexy approach just like array map above.

function capitalize(str) {    return str        .split(' ')        .reduce((prev, current) => `${prev} ${current[0].toUpperCase() + current.slice(1)}`, '')}

Solution #3: for-of loop

• Below is an alternative solution that can be used but it creates a variable to push results which array reduce solves easily. I see this as an OK option.

function capitalize(str) {    const words = [];    for (let word of str.split(' ')) {        words.push(word[0].toUpperCase() + word.slice(1));    }    return words.join(' ');}

Happy coding and good luck if you are interviewing!

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