This PR fixes deviations in our AST format compared to TSEStree. They
are mostly a leftover for when I first started working on it and based
it off of babel instead.
One of the key changes why the changeset is a bit bigger is that
TSEStree uses `undefined` instead of `null` as the empty value for type
nodes. This is likely influenced by `tsc` which use `undefined`
everywhere. The rest of the nodes use `null` though. It's a little
weird, but for now it might be better to align.
(extracted from https://github.com/denoland/deno/pull/27977)
This commit adds an unstable lint plugin API.
Plugins are specified in the `deno.json` file under
`lint.plugins` option like so:
```
{
"lint": {
"plugins": [
"./plugins/my-plugin.ts",
"jsr:@deno/lint-plugin1",
"npm:@deno/lint-plugin2"
]
}
}
```
The API is considered unstable and might be subject
to changes in the future.
Plugin API was modelled after ESLint API for the
most part, but there are no guarantees for compatibility.
The AST format exposed to plugins is closely modelled
after the AST that `typescript-eslint` uses.
Lint plugins use the visitor pattern and can add
diagnostics like so:
```
export default {
name: "lint-plugin",
rules: {
"plugin-rule": {
create(context) {
return {
Identifier(node) {
if (node.name === "a") {
context.report({
node,
message: "should be b",
fix(fixer) {
return fixer.replaceText(node, "_b");
},
});
}
},
};
},
},
},
} satisfies Deno.lint.Plugin;
```
Besides reporting errors (diagnostics) plugins can provide
automatic fixes that use text replacement to apply changes.
---------
Co-authored-by: Marvin Hagemeister <marvin@deno.com>
Co-authored-by: David Sherret <dsherret@gmail.com>
This PR changes the underlying buffer backed AST format we use for
JavaScript-based linting plugins. It adds support for various new types,
makes traversal code a lot easier and is more polished compared to
previous iterations.
Here is a quick summary (in no particular order):
- Node prop data is separate from traversal, which makes traversal code
so much easier to reason about. Previously, it was interleaved with node
prop data
- spans are in a separate table as well, as they are rarely needed.
- schema is separate from SWC conversion logic, which makes
- supports recursive plain objects
- supports numbers
- supports bigint
- supports regex
- adds all SWC nodes
Apologies, this is kinda a big PR, but it's worth it imo.
_Marking as draft because I need to update some tests tomorrow._
