Clippy & rustfmt — Linting and Formatting

eslint + prettier → clippy + rustfmt

In TypeScript projects you typically wire up two separate tools: eslint for catching logical mistakes and enforcing code patterns, and prettier for opinionated formatting. Each needs its own config, its own plugins, and sometimes they conflict.

Rust ships two first-party tools that are always present:

TypeScript	Rust	Purpose
`eslint`	`cargo clippy`	Catches bugs, anti-patterns, and non-idiomatic code
`prettier`	`cargo fmt`	Enforces a single canonical style
`.eslintrc`	`clippy.toml` or `#[allow(...)]`	Configuration
`.prettierrc`	`rustfmt.toml`	Formatting overrides

cargo fmt — formatting

# TypeScript
npx prettier --write "src/**/*.ts"

# Rust
cargo fmt              # format all files in the workspace
cargo fmt --check      # CI mode: exit 1 if any file would change

cargo fmt wraps rustfmt. The defaults are the official style and almost no one overrides them. A minimal rustfmt.toml at the project root can adjust a few options:

# rustfmt.toml (optional — most projects have none)
max_width = 100
edition = "2021"

cargo clippy — linting

# TypeScript
npx eslint src/

# Rust
cargo clippy                  # warn on lint violations
cargo clippy -- -D warnings   # treat every warning as a compile error (use on CI)

// eslint might warn: prefer const
let items = getItems();

// eslint might warn: no-unused-vars
function helper(x: number, _y: number) {
  return x * 2;
}

// Clippy warns: this could be written more idiomatically
let v: Vec<i32> = vec![1, 2, 3];
let doubled: Vec<i32> = v.iter().map(|x| x * 2).collect();

// Clippy warns: use .is_empty() instead of .len() == 0
if doubled.len() == 0 {
    println!("empty");
}
// Idiomatic version:
if doubled.is_empty() {
    println!("empty");
}

Suppressing a lint

// Suppress one lint on the next item
#[allow(clippy::needless_pass_by_value)]
fn process(data: Vec<u8>) { /* ... */ }

// Suppress across the whole file (put at crate root)
#![allow(dead_code)]

Recommended CI configuration

Run both tools on CI so formatting and lint errors are caught before merge:

cargo fmt --check
cargo clippy -- -D warnings
cargo test

These are bash commands to run in your terminal or CI pipeline — there is no runnable browser snippet for linter invocations.