[Feature Request] Add a way to intentionally insert line break inside a `oneLine`

[ricokahler]

First off, thanks for an amazing and simple library! I like using oneLine to keep long text within 100 characters 🙌. However, (as far as I know) there is no way to add an intentional line break in a oneLine.

For example, I'll have a longer paragraph like so:

const longParagraph = oneLine`
  Four score and seven years ago our fathers brought forth on this continent, a new nation,
  conceived in Liberty, and dedicated to the proposition that all men are created equal.

  Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived
  and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to
  dedicate a portion of that field, as a final resting place for those who here gave their lives
  that that nation might live. It is altogether fitting and proper that we should do this.
`;

and my intention would be to add two intentional line breaks after "created equal." and maybe an additional line break after "should do this.".

I have three proposals to get this feature:

1. add an extra directive to import that when oneLine (or any other tag) sees it, it will add the intentional line break

import { oneLine, NEW_LINE } from 'common-tags';

const longParagraph = oneLine`
  Four score and seven years ago our fathers brought forth on this continent, a new nation,
  conceived in Liberty, and dedicated to the proposition that all men are created equal.${NEW_LINE}
  ${NEW_LINE}
  Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived
  and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to
  dedicate a portion of that field, as a final resting place for those who here gave their lives
  that that nation might live. It is altogether fitting and proper that we should do this.${NEW_LINE}
`;

2. import or add some special directive that allows you to escape new lines (or even other things like tabs).

import { oneLine, escape } from 'common-tags';

const longParagraph = oneLine`
  Four score and seven years ago our fathers brought forth on this continent, a new nation,
  conceived in Liberty, and dedicated to the proposition that all men are created equal.${escape('\n')}
  ${escape('\n')}
  Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived
  and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to
  dedicate a portion of that field, as a final resting place for those who here gave their lives
  that that nation might live. It is altogether fitting and proper that we should do this.${escape('\n')}
`;

instead of importing escape, there could be an escape sequence similar to javascript's backslashes \

3. create a brand new tag that will add insert a single line break when two line breaks are present (similar to how markdown works)

import { paragraph } from 'common-tags';

const longParagraph = paragraph`
  Four score and seven years ago our fathers brought forth on this continent, a new nation,
  conceived in Liberty, and dedicated to the proposition that all men are created equal.


  Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived
  and so dedicated, can long endure. We are met on a great battle-field of that war. We have come to
  dedicate a portion of that field, as a final resting place for those who here gave their lives
  that that nation might live. It is altogether fitting and proper that we should do this.

`;

The logic for the paragraph tag (could use renaming) is for every two consecutive line breaks (without considering whitespace), it will insert one line break. The rest of the line breaks will be ignored.

I would be willing to work on the PRs after I get your blessing for any or all of the above proposals. I think both 2 and 3 are worth implementing.

Let me know what you think and I apologize if I missed something!

[reidgould]

+1. I'd like a set of tags that work exactly like YAML Multiline Strings with the double newline in folded style to produce a newline in the result, the final chomping option, and (like the tags in this package already do) default chomping of the first newline.

[fatfisz]

@ricokahler I think both 2 & 3 are worth considering. If you still want to tackle them, PRs are welcome! In that case please create two separate PRs for those features.

@reidgould Do I understand correctly that proposal number 3. is what you have in mind or is it something different?

[vipulbhj]

Is this still open, I would like to work on this. Having a paragraph tagged literal would be great. And the escaping function also sounds like it can open up a lot of new use cases

[fatfisz]

Sure, go ahead! I think the second proposal is the best one because it's the most explicit. Would you like to work on that?

[ricokahler]

@vipulbhj i opened this issue and then i got busy, then i forgot to work on it 😅

please finish what i started lol

[vipulbhj]

@ricokahler sure, which one should we go for ??

[vipulbhj]

const paragraph = createTag(
  replaceResultTransformer(/(?:\n+)/g, '\n'),
  trimResultTransformer(),
);

Does this look okay to you guys ??

[abyss]

+1. I'm fond of method 3, personally. I may attempt to get a PR for this but just incase I don't - maybe someone will finish this?

Edit: Spent some time on it and couldn't figure it out. Hopefully someone better at regex can pick this up

[mrmachine]

Definitely the 3rd option, like Markdown. Hard wrapped paragraphs should be restored to one line, but distinct paragraphs should remain intact.

[FoxxMD]

@vipulbhj this was close but did not work for me.

This works to implement method 3:

const doubleReturnNewline = new TemplateTag(
    // remove instances of single line breaks
    replaceResultTransformer(/(?<=.)\n(?!\n+)/g, ''),
    // replace instances of two or more line breaks with one line break
    replaceResultTransformer(/(?<=.)\n{2,}/g, '\n'),
    trimResultTransformer(),
);

May only work for server/node usage due to lookbehind/lookahead