Javascript regex challenge issue

JavaScript
1

Tell us what’s happening:
The problem is that even when you write the right solution the test aren’t getting passed. The following code solves the challenge, but 2/5 of the tests fail.
Apologies for my grammar and spelling.

Your code so far

let myString = "Eleanor Roosevelt";
let myRegex = /(Franklin|Eleanor).*Roosevelt/g; 
let result = myRegex.test(myString);

Your browser information:

User Agent is: Mozilla/5.0 (X11; Linux x86_64; rv:71.0) Gecko/20100101 Firefox/71.0.

Challenge: Check For Mixed Grouping of Characters

Link to the challenge:
https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/regular-expressions/check-for-mixed-grouping-of-characters

2

the problem is the use of the g flag that advance the index at which the test method start checking, making tests fail unexpectedly

to find out more about the g flag with the test method you can look at the documentation on the test method

1 Like
4

the g flag with the test method moves where the check starts so it causes issues if you always want to check the string from the first character

5

Can you run this /(Eleanor|Franklin).*Roosevelt/g.test('Franklin D. Roosevelt') code in your browser console. It will return true. why the problem is not causing.

7

Screenshot%20from%202019-10-20%2016-14-06

8

yes, this work, but the tests use the same regex multiple times.

let re = /(Eleanor|Franklin).*Roosevelt/g;
re.test('Franklin D. Roosevelt'); // true 
re.test('Franklin D. Roosevelt'); // and this one?
9

I deleted that post… check my last post instead

10

Screenshot%20from%202019-10-20%2016-25-01

but It working with odd number of times i check regex?

11

because when the test method returns false then the check start again at the beginning of the string.

try without g flag, everything will return true

If the regex has the global flag set, test() will advance the lastIndex of the regex. A subsequent use of test() will start the search at the substring of str specified by lastIndex ( exec() will also advance the lastIndex property). It is worth noting that the lastIndex will not reset when testing a different string.