Replace a character of a string

Question

I have a string that looks like this: [TITLE|prefix=a].

From that string, the text |prefix=a is dynamic. So it could be anything or emp

Answer 1

You need to remember to use \\ in a regular string literal to define a single literal backslash.

Then, you need a pattern like

/(\[TITLE(?:\|[^\][]*)?)]/gi

See the regex demo. Details:

• (\[TITLE\|[^\][]*) - Capturing group 1:
  • \[TITLE - [TITLE text
  • (?:\|[^\][]*)? - an optional occurrence of a | char followed with 0 or more chars other than ] and [
• ] - a ] char.

Inside your JavaScript code, use the following to define the dynamic pattern:

const regex = new RegExp(`(\\[${x}\\|[^\\][]*)]`, 'gi');

See JS demo:

let str = 'Lorem ipsum [TITLE|prefix=a] dolor [sit] amet [consectetur] [TITLE]';
const x = 'TITLE';
const regex = new RegExp(`(\\[${x}(?:\\|[^\\][]*)?)]`, 'gi');
str = str.replace(regex, "$1|suffix=z]");
console.log(str);
// => Lorem ipsum [TITLE|prefix=a|suffix=z] dolor [sit] amet [consectetur]

Answer 2

I think the solution to your problem would look similar to this:

let str = 'Lorem ipsum [TITLE|prefix=a] dolor [sit] amet [consectetur]';

str = str.replace(/(\[[^\|\]]+)(\|[^\]]*)?\]/g, "$1$2|suffix=z]");

console.log(str);