JavaScript regex to find string

Question

I have a string and two words from a dictionary and I am trying to know if in my string there are words that are not my dictionary words.

var string = 'foobarfooba';
var patt = new RegExp("[^(foo|bar)]");// words from dictionary
var res = patt.test(string);
console.log(res);//return false

It should return true because in my string there is also 'ba', but it return false.

• Phil: Lose the square brackets. You're not looking for a character class
• befzz: var patt = /foo|bar/;

Answer 1

Same as Phil commented in your question, you have to get rid of the character class:

[^(foo|bar)]
^-- here --^

Character classes are used to match (or not match if you use ^) specific unsorted characters.

Just use:

var patt = new RegExp("(?:foo|bar)");// words from dictionary

If you want to ensure that all the string matches your regex, you can use:

^(?:foo|bar)+$

Working demo

If you want to capture the invalid words, you can use a regex with capturing groups like this:

^(?:foo|bar)+|(.+)$

Working demo

Match information

MATCH 1
1. [9-11] `ba`

• Giuseppe federico: But I need to know if there are some string like 'ba' that is different of my word
• Giuseppe federico: it still returns false
• Federico Piazza: @Giuseppefederico that's ok, it returns false because there are words not matching your regex. Isn't it what you want?
• Giuseppe federico: Maybe I didn't explain well, I need to know that there is 'ba' that it is not in my regex
• Giuseppe federico: I am sorry you are right, could you explain me the meaning of ?: and +$