What are customers saying?
The café has thousands of reviews. Build the analysis functions with maps and sets so they stay fast as reviews pile up.
Clean words first
This project uses nothing but arrays, maps and sets, yet it handles thousands of reviews comfortably — a good reminder that the right basic structure beats clever code.
Every analysis starts with the same step: turn messy text into clean words. Lowercase everything so "Great" and "great" count together, and keep only letters so punctuation doesn't create fake words like "tea!". A regular expression with match does it in one line and returns an array you can count, group and sort.
function words(text) {
return text.toLowerCase().match(/[a-z]+/g) ?? [];
}
console.log(words("Great momo, great TEA!"));