denoland/deno_lint
Blazing fast linter for JavaScript and TypeScript written in Rust
deno_lint
A Rust crate for writing fast JavaScript and TypeScript linters.
This crate powers deno lint, but is
not Deno specific and can be used to write linters for Node as well.
Supports recommended set of rules from ESLint and @typescript-eslint out of
the box with no config.
See the roadmap
Supported rules
Visit https://lint.deno.land for the list of available rules.
Performance
Blazing fast, see comparison with ESLint:
[
{
"name": "deno_lint",
"totalMs": 105.3750100000002,
"runsCount": 5,
"measuredRunsAvgMs": 21.07500200000004,
"measuredRunsMs": [
24.79783199999997,
19.563640000000078,
20.759051999999883,
19.99068000000011,
20.26380600000016
]
},
{
"name": "eslint",
"totalMs": 11845.073306000002,
"runsCount": 5,
"measuredRunsAvgMs": 2369.0146612000003,
"measuredRunsMs": [
2686.1039550000005,
2281.501061,
2298.6185210000003,
2279.5962849999996,
2299.2534840000008
]
}
]Benchmarks are run during CI on Ubuntu, using the same set of rules for both
linters. Test subject is oak server
consisting of about 50 files. See ./benchmarks/ directory for
more info.
Node.js bindings
If you want to use deno_lint with Node, please refer to
@node-rs/deno-lint package
which provides programmatic API as well as Webpack loader for deno_lint.
Example
examples/dlint/main.rs provides a minimal standalone binary demonstrating how
deno_lint can be used as a crate.
# Build standalone binary
$ cargo build --example dlint
$ ./target/debug/examples/dlint --help
dlint
USAGE:
dlint <SUBCOMMAND>
FLAGS:
-h, --help Prints help information
-V, --version Prints version information
SUBCOMMANDS:
help Prints this message or the help of the given subcommand(s)
rules
run
$ ./target/debug/examples/dlint run ../deno/std/http/server.ts ../deno/std/http/file_server.ts
(no-empty) Empty block statement
--> ../deno/std/http/server.ts:93:14
|
93 | } catch {}
| ^^
|
(no-empty) Empty block statement
--> ../deno/std/http/server.ts:111:44
|
111 | while ((await body.read(buf)) !== null) {}
| ^^
|
(no-empty) Empty block statement
--> ../deno/std/http/server.ts:120:41
|
120 | constructor(public listener: Listener) {}
| ^^
|
(ban-untagged-todo) TODO should be tagged with (@username) or (#issue)
--> ../deno/std/http/file_server.ts:5:0
|
5 | // TODO Stream responses instead of reading them into memory.
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
(ban-untagged-todo) TODO should be tagged with (@username) or (#issue)
--> ../deno/std/http/file_server.ts:6:0
|
6 | // TODO Add tests like these:
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
(ban-untagged-todo) TODO should be tagged with (@username) or (#issue)
--> ../deno/std/http/file_server.ts:137:0
|
137 | // TODO: simplify this after deno.stat and deno.readDir are fixed
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
(no-empty) Empty block statement
--> ../deno/std/http/file_server.ts:155:16
|
155 | } catch (e) {}
| ^^
|
Found 7 problemsFor more concrete implementation visit
deno
Developing
Make sure to have latest stable version of Rust installed, see
rust-toolchain.toml.
// check version
$ rustc --version
// build all targets
$ cargo build --all-targets
// test it
$ cargo testGenerating flamegraph (Linux)
Prerequisites:
- Install
perf,
stackcollapse-perf,
c++filt
and
flamegraph
$ RUSTFLAGS='-g' cargo build --release --all-targets # build target
$ sudo perf record --call-graph dwarf ./target/release/examples/dlint benchmarks/oak/**.ts # create performance profile
$ perf script | stackcollapse-perf | c++filt | flamegraph > flame.svg # generate flamegraphYou can use
rust-unmangle
or rustfilt instead of c++filt.
These commands can take a few minutes to run.
Contributing
-
If you are going to work on an issue, mention so in the issue comments
before you start working on the issue. -
Please be professional in the forums. We follow
Rust's code of conduct
(CoC) Have a problem? Email ry@tinyclouds.org. -
Ask for help in the community chat room.
Submitting a Pull Request
Before submitting, please make sure the following is done:
- That there is a related issue and it is referenced in the PR text.
- There are tests that cover the changes.
- Ensure
cargo testpasses. - Format your code with
deno run --allow-run tools/format.ts - Make sure
deno run --allow-run --allow-env tools/lint.tspasses. - If you've added a new rule, open a PR to
https://github.com/denoland/deno-docs with a documentation for a rule.