Search for regex terms independent of symbol

So I have this string right here, it’s a registration number:

12.325.767/0001-90

And I want to create a regex when I type “23”, return for me the “2.3” or if I type “700”, return for me “7/00” or if I type “19”, return “1-9”.

So, I want to get the number even if there is a symbol in the middle.

I’m trying this on Javascript, here what I have:

const cnpj = "12.325.767/0001-90";
const search = "12";

const regex = new RegExp(`(${search})`, "i");

const result = cnpj.split(regex);

output:

[ '', '12', '.325.767/0001-90' ]

This output is correct, because I put a number that does not have symbols in its composition.

But when I try to search a number that contains a symbol in its composition, is not splitted.

Answer

You could convert the user input into a RegExp that has symbols between each digit. For example, 12 becomes 1[.,/:;]?2, so you search if there is one or none of those symbols between the numbers.

If you used a function like this, you would get the result you want:

function underline(input, text) {
    const symbols = '.,/:;';
    const reInput = input.split('').join(`[${symbols}]?`);
    const re = new RegExp(reInput);

    return re.exec(text);
}

for user input 23, with your example text 12.325.767/0001-90, this function returns the following result

[ '2.3', index: 1, input: '12.325.767/0001-90', groups: undefined ]

You can substring from that, using the index and the result length, or make a more complex RegExp, like this:

function underline(input, text) {
    const symbols = '.,/:;';
    const reInput = input.split('').join(`[${symbols}]?`);
    const reText = '(.*?)(' + reInput + ')(.*)';
    const re = new RegExp(reText);
    const [_, ...result] = re.exec(text);
    
    return result;
}

This returns the array you expected.

[ '1', '2.3', '25.767/0001-90' ]