I agree with a lot of comments that it's minimal, but in my opinion that is a good thing. I'm a big fan of Obsidian, and of the things I like about it is the data source is all markdown files. Markdown is meant to be very lightweight and portable, and overcomplicating it will limit adoption and extensibility (imagine markdown vs pdf).
JSON Canvas seems to follow in that spirit by being very lightweight, so a lot of implementation details (i.e. how are files rendered, what file formats are supported, etc), edit tags, etc) are left open to implementation.
Markdown and JSON are meant to be non-opague file formats that prioritizes portability and human readability over other features. An application format like Sqlite has a lot of benefits over markdown, but it loses the benefits of text based formats like being compatible with git and is less portable.
What I would like to see is a convention for extending the node and edge definitions, similar to frontmatter in markdown files- something that is not required for basic rendering but is a nice-to-have for applications to consume) - that way portability between apps of varying complexity can be maximized while still allowing for more complex features that some apps might implement. Markdown has the benefit of supporting extensions (for example like tables in GFM) - apps that are not compatible can still render the unsupported markup. But there should be an explicit way to extend open JSON formats.
Some feedback off the top of my head and from reading the comments:
1. *Specifying node ordering*. Obsidian seems to just send whatever is last touched to the top, but this makes a common feature in many apps (move up/down/back/front) more difficult to impement
2.*More explicit definition for line shape*. Adding a way to "bend" a line in a specific way. Useful for creating more complex diagrams.
3. *Relations between nodes*. Group nodes contain child nodes, but the spec doesn't specify how the child nodes are defined. I would expect it to have a `children` property to nest nodes. Obsidian seems to implicitly link nodes to groups based on whether their bounds intersect. This makes it difficult to implement some common features:
a. nodes that exist outside of the bounds of its group, for example a node that "floats" just outside of the edge of the group's borders.
b. nodes that are not part of a group even though it exists within the bounds of that group.
There are many different ways for a canvas app to extend the spec to implement those features, but it seems like something that should be defined in the spec to maximize portability
4. *Extensibility.* Either explicitly support or provide a standard for defining more styles for nodes and edges, such as stroke width, stroke style, rotation, etc. It seems like "color" should be a part of this as well, rather than being an explicit property of a node.
5. *Embeds.* Supporting "embeds" as a node type. I even think the "file" node should be redefined as `embed` with a `uri` property to support different schemes (`file://`, `oembed://`, `https://`) and maybe a `mime-type` (`text/markdown`, `image/webp`). The file node's "subpath" property seems to be only relevant for markdown files, so I think that should be an extension rather than an explicitly defined.
6.*YAML* :) (Should just seemlessly convert from json, but yaml is more readable than json)
Being able to design standards that evolve over time and making tough decisions about what what to make explicit and what to leave implicit is a skill I want to improve on as a developer this year. Does anyone have any resource recommendations or best practices to recommend for me to research?