Code Style Guide

// Modifiers are automatically sorted
private final def foo() = ???  // Good order
final private def foo() = ???  // Auto-fixed

// Avoid infix notation (auto-converted)
list.map(x => x + 1)  // Good
list map (x => x + 1) // Auto-fixed to method call syntax

// Redundant braces in string interpolation removed
s"Hello ${name}"     // Auto-fixed to s"Hello $name"
s"Hello $name"      // Good

// Redundant import selectors removed automatically
import foo.{Bar => Bar}  // Auto-fixed to import foo.Bar
import foo.Bar           // Good

// build.sbt and project/** files
runner.dialect = scala213

// Prefer const/let over var
const name = 'Lichess';  // Good
let count = 0;           // Good
var flag = true;         // Warning: use const or let

// No duplicate imports
import { foo } from './module';
import { bar } from './module';  // Error: combine into one import

// Correct:
import { foo, bar } from './module';

// Prefix unused variables with underscore
function handler(_event: Event, data: any) {
  // _event is intentionally unused
  console.log(data);
}

// Always reject with Error objects
Promise.reject(new Error('Something went wrong'));  // Good
Promise.reject('error message');                     // Error

// No callbacks in promises
promise.then(data => {
  callback(data);  // Error: avoid mixing callbacks and promises
});

// No multiple resolves
Promise((resolve) => {
  resolve(1);
  resolve(2);  // Error: promise already resolved
});

// Use Record instead of index signatures when possible
type Config = Record<string, string>;  // Good
type Config = { [key: string]: string };  // Error

// No empty interfaces
interface Props {}  // Error: use type alias or add properties

// No unnecessary type assertions
const num = 5 as number;  // Error: already a number
const num = 5;            // Good

// No unnecessary template expressions
const str = `${name}`;    // Error: use name directly
const str = name;         // Good

// Prefer modern array methods
arr.flat()              // Good
arr.reduce((a,b) => a.concat(b), [])  // Error: use flat()

arr.flatMap(x => [x, x * 2])  // Good
arr.map(x => [x, x * 2]).flat()  // Error: use flatMap()

arr.some(x => x > 5)    // Good
arr.find(x => x > 5) !== undefined  // Error: use some()

{
  "files": ["bin/**", "cron/**"],
  "rules": {
    "no-unused-vars": "off",
    "unicorn/prefer-array-some": "off"
  }
}

// Use legacy color notation with numbers for alpha
rgba(255, 0, 0, 0.5)  // Good
rgb(255 0 0 / 50%)    // Error: use legacy notation

// Hue as number, not degree
hsl(120, 100%, 50%)   // Good
hsl(120deg, 100%, 50%)  // Error: use number

// Any pattern allowed for variables and classes
$primaryColor: #3893E8;  // Allowed
$primary-color: #3893E8;  // Also allowed

// SCSS global functions allowed (color functions, etc.)
.button {
  background: darken($primary, 10%);  // Allowed
}

// Operators can span multiple lines
.container {
  width: $base-width
    + $margin;  // Allowed
}