freeCodeCamp/guide/english/certifications/javascript-algorithms-and-data-structures/regular-expressions/specify-exact-number-of-matches/index.md

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Specify Exact Number of Matches

Specify Exact Number of Matches

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Hints

Hint 1

We see that the answer is simply finding 4 m's in a row. The first anwser would be to match EXACTLY 4 times the character so we shall implement as following:

let timRegex = /m{4}/;

This solution is incorrect because you wont pass the final test case ("Timber" with 30 m's in it) as there are multiple times mmmm in a row of 30 m. You should try to get no more than (4 times m) mmmm.

Hint 2

Based on the above I will try to specify exactly the characters before and after 4 times m! Remember: e.g. /b/ is a string literal for the word b so what if before and after mmmm we add ALL missing letters?

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Solutions

Solution 1 (Click to Show/Hide)

From hint 1 we defined how to find mmmm in the timStr. From hint 2 we observe that we need to find the word Timmmmber=Tim{4}ber. We simpply add the exact word in our timRegex value and the final result is:

let timStr = "Timmmmber";
let timRegex = /Tim{4}ber/; // Change this line
let result = timRegex.test(timStr);