const regex = /(\[[^\][]*]\()https?:\/\/docs\.google\.com\/document\/d\/([^\s\\\/)]+)[^\s)]*\)/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(\\[[^\\][]*]\\()https?:\\\/\\\/docs\\.google\\.com\\\/document\\\/d\\\/([^\\s\\\\\\\/)]+)[^\\s)]*\\)', 'gm')
const str = `# Title
Text text text.
Text 1 text 1 text 1, abc.
More text
Bullet points
- [abc]
- [bla]
- [cba]
[Text](https://docs.google.com/document/d/unique-doc-id-here/edit)
## Title 2
More text:
- A
- B
- C
- D
Text text text text [url1](https://docs.google.com/document/d/2x2my-DRqfSidOsdve4m9bF_eEOJ7RqIWP7tk7PM4qEr) text.
**BOLD.**
## Title
Text2 text1 text3 text
[url2](https://docs.google.com/document/d/4x2mrhsqfGSidOsdve4m9bb_wEOJ7RqsWP7tk7PMPqEb/edit#bookmark=id.mbnek2bdkj8c) text.
More text here
[bla](https://docs.google.com/document/d/6an7_b4Mb0OdxNZdfD3KedfvFtdf2OeGzG40ztfDhi5o9uU/edit)
`;
const subst = `$1[REPLACEMENT]$3`;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions