freeCodeCamp Challenge Guide: Positive and Negative Lookahead

Positive and Negative Lookahead


Hints

Hint 1

Remeber to use 2 lookaheads to check the patterns in the string. The first lookahead is very similar to that given in the example - ‘(?=\w{3,6})’ - only the lower-number 3 is too low for our test cases, and an upper-number is completely unneccesarry. This first lookahead is only used to find a string consisting of a certain amount of characters. A second lookahead must be used to check for consecutive numerical values at the end of the string.

Hint 2

The second lookahead is also similar to that given in the example - (?=\D*\d) - however, this expression too must be modified to pass all test cases. Remember to specify the exact amount of numbers you want to appear at the end of the string.


Solutions

Solution 1 (Click to Show/Hide)
let sampleWord = "astronaut";
var pwRegex =  /^\D(?=\w{5})(?=\w*\d{2})/;
let result = pwRegex.test(sampleWord);
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