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Show HN: Mermaid ASCII Diagrams

215 points by AlexanderGrooff - 43 comments
quuxplusone [3 hidden]5 mins ago
Some nits:

The "Example" buttons don't jump out at me; I found them but it took a while. Also consider labeling them with their point, e.g. "Example 3: Color"

If you change the input text to something well-formed, the graph seems to update immediately. But if you change it to something ill-formed, the graph doesn't update immediately — and then if you click "Generate" manually, it blanks the input box. Either this is a bug, or the "Generate" button doesn't do what I think it does (i.e. generate output). Again, adding a noun to the verb might help. Or just adding some usage information somewhere on the page.

For those like me who've never heard of "Mermaid," apparently it's like GraphViz's dot language but different. https://github.com/mermaid-js/mermaid I tried the flowchart example from Mermaid's own README, but it didn't come out right: looks like the shape characters [] and {} aren't handled.

lordswork [3 hidden]5 mins ago
Counter-nit: I found the examples within a few seconds.
brink [3 hidden]5 mins ago
Counter-counter-nit: I did not.
wigster [3 hidden]5 mins ago
nor i
matt3210 [3 hidden]5 mins ago
Same, I had no idea there were examples until I read this.
AlexanderGrooff [3 hidden]5 mins ago
Thanks for the feedback! I agree that the web UI can be improved (quite) a bit, most of my efforts went into the actual generation of the diagrams. I'll have a look at prettifying it.
virtualritz [3 hidden]5 mins ago
This obviously needs a direct pipe into Svgbob!

https://ivanceras.github.io/svgbob-editor/

Myrmornis [3 hidden]5 mins ago
https://d2lang.com/ is really nice.

Also I used to use https://swimlanes.io/ before d2.

pkaye [3 hidden]5 mins ago
Needs to have a '+' and the elbows and T intersections.
comebhack [3 hidden]5 mins ago
I have been using Monodraw for a long time: https://monodraw.helftone.com/

It's a macOS app and I've found it great. However if given an ASCII diagram, you cannot edit it with the same ease as creating a new one (e.g. reflowing text or resizing boxes).

I really like the idea of having the mermaid source and the ASCII diagram together, so you could use the source to change the diagram if needed. But I feel that would feel cluttered to have both in a plain text file or comment, where ASCII diagrams shine.

nunobrito [3 hidden]5 mins ago
Hey, where are the mermaids?!?

But now seriously.. the diagrams are working really well for simple examples, thank you so much for sharing this tool. I have bookmarked your page, my documentation is based on text files and often have to build these kind of diagrams too.

The example buttons took me a while to be found, but are good for syntax explanation. Thank you for making this available.

AlexanderGrooff [3 hidden]5 mins ago
Thanks for the kind words!
ithkuil [3 hidden]5 mins ago
Is there something that can turn those ascii diagrams back into mermaid sources?

I tried the first example with gpt-o1 and the result wasn't bad:

    graph LR
    A --> B --> D
    A --> C
    B --> C
    D --> C
would a smaller model but fine tuned on many syntetic renderings do a better job?
jonahx [3 hidden]5 mins ago
Nice work, I love ascii diagrams. Especially useful when you want a visual explanation that can be embedded directly in source code.

Small nit on layout: 90 degree joints should use "+" in the connecting lines, as they do in the boxes.

AlexanderGrooff [3 hidden]5 mins ago
Thanks for the recommendation. I've added the "+" corners in v0.5.1.
tiagoafpereira [3 hidden]5 mins ago
PhilipRoman [3 hidden]5 mins ago
I use https://metacpan.org/dist/Graph-Easy/view/bin/graph-easy There is a package perl-graph-easy for it in AUR (it's a command line frontend for the perl library)
Lorak_ [3 hidden]5 mins ago
Are you planning to support more of mermaids features? I tried one example where this could be useful to me - Mermaids gitGraph - and it looks like it's not supported.
AlexanderGrooff [3 hidden]5 mins ago
Yes, over the course of time I want to increase the coverage of the Mermaid syntax.

PS: it's open source so feel free to help out ;) https://github.com/AlexanderGrooff/mermaid-ascii

zczc [3 hidden]5 mins ago
prmoustache [3 hidden]5 mins ago
graph TD

project is called Mermaid ASCII -->|expectation| It supports mermaidjs syntax

It supports mermaidjs syntax -->|I tried| It doesn't

It doesn't -->|conclusion| I am a bit bummed

https://mermaid.js.org/syntax/examples.html

AlexanderGrooff [3 hidden]5 mins ago
The example you post works just fine ;)

On a serious note, yes not all syntax noted in the Mermaid docs work yet. I'm planning on adding more coverage of the Mermaid syntax over time. For now the basics work and (hopefully) shows its potential.

prmoustache [3 hidden]5 mins ago
Yeah, first try I copy pasted the pie charts example wondering how it would render in ascii and was noooo
girvo [3 hidden]5 mins ago
Hah we rely on Mermaid a _heap_ at work for building internal dependency graphs from `yarn info` JSON data and a super lazy depth-first graph haha. Super useful, nice to see another renderer!

ts-directed-graph outputs Mermaid :)

This tool seems way more useful for hand-made ones, definitely bookmarking

danpalmer [3 hidden]5 mins ago
Out of interest have you managed to get Mermaid graphs rendering outside of a browser?

I was trying to do this a while back so I could do server side rendering of graphs, but it seemed to depend strongly on the presence of a DOM. Couldn’t quite get it working with JS-DOM either.

pjungwir [3 hidden]5 mins ago
I've used [mmdc](https://github.com/mermaid-js/mermaid-cli) to generate mermaid images from a Makefile. It looks like it is implemented with puppeteer, so perhaps it doesn't quite fit your request. But if you just want something you can use at the cli, it is great.
the_arun [3 hidden]5 mins ago
I use this for generating AWS deployment diagrams, which is kinda similar - https://github.com/mingrammer/diagrams
piedpiper99 [3 hidden]5 mins ago
I supposed it's good for basic usage. I just tried a more complex graph and it didn't render well.
abraxas [3 hidden]5 mins ago
In the age of AI someone automated Mentifex[1]!

[1] https://nothingisreal.com/mentifex_faq.html

flykespice [3 hidden]5 mins ago
Wow! this will come pretty in hand when building plaintext documentation using diagrams.
nlake906 [3 hidden]5 mins ago
love it, will definitely be using it for sketching documentation in comments for SQL sprocs, etc.

One request: support for self-reference, i.e. "A --> A", "A --> A & B"

AlexanderGrooff [3 hidden]5 mins ago
Thanks, that's a good suggestion. I'm also noticing that's not working as intended.
AlexanderGrooff [3 hidden]5 mins ago
Fixed in 0.5.0. Give it a try!
ewalk153 [3 hidden]5 mins ago
This would be great to build into project readme workflows.
kitd [3 hidden]5 mins ago
You can already use Mermaid in GitHub markdown:

https://docs.github.com/en/get-started/writing-on-github/wor...

mcraiha [3 hidden]5 mins ago
dmonitor [3 hidden]5 mins ago
edflsafoiewq [3 hidden]5 mins ago
I don't like that it renders controls on top of the diagram.
octopusRex [3 hidden]5 mins ago
I'm disappointed. I was actually expecting lovely ascii art pictures of mermaids.
derfnugget [3 hidden]5 mins ago
Same. This is more than a nit. It's pretty much a need.
kleiba [3 hidden]5 mins ago
airstrike [3 hidden]5 mins ago

         ┌──────────────┐
         │ It's 2024... │
         └───────┬──────┘
                 │
    ╔════════════╧═════════════╗
    ║    I wish box drawing    ║
    ║ characters were the norm ║
    ╚══════════════════════════╝