Naming Conventions & Roman Numerals

Practical Snippet

Key points: (1) judge strictness by scope — exported names must follow the language standard strictly, while internal locals may use team habit; (2) converters differ on acronyms and consecutive capitals (the same HTTPServer yields three results), so use an explicit mapping table plus snapshot tests instead of relying on inference; (3) prefix booleans with is/has/can/should, name collections in the plural and single elements in the singular; (4) avoid zero-information names like data/info/obj; (5) convert names explicitly at every language or layer boundary and lock the field names with tests, because conventions alone will eventually be missed.

// ① 常见风格的构成规则（正则可直接用于校验）
const STYLES = {
  camelCase:    /^[a-z][a-zA-Z0-9]*$/,        // myVariable
  PascalCase:   /^[A-Z][a-zA-Z0-9]*$/,        // MyVariable
  snake_case:   /^[a-z][a-z0-9_]*$/,          // my_variable
  kebab_case:   /^[a-z][a-z0-9-]*$/,          // my-variable
  SCREAMING:    /^[A-Z][A-Z0-9_]*$/,          // MY_VARIABLE
}

// ② 按作用域决定严格程度
function checkName(name, scope) {
  const ok = Object.entries(STYLES).find(([, re]) => re.test(name))
  return {
    valid: !!ok,
    style: ok ? ok[0] : null,
    // 导出的名字必须是语言标准风格，内部变量可放宽
    enforced: scope === 'export' ? ['camelCase', 'PascalCase'] : Object.keys(STYLES),
  }
}
console.log(checkName('myVar', 'export'))      // { valid: true, style: 'camelCase' }
console.log(checkName('my_var', 'export'))     // 导出命名不合 JS 惯例

// ③ 🔴 转换库对缩写/大写的处理各不相同 ⇒ 关键名称用显式映射
const EXPLICIT = { HTTPServer: 'http_server', XMLHttpRequest: 'xml_http_request' }
function toSnake(name) {
  if (EXPLICIT[name]) return EXPLICIT[name]          // 优先查表
  return name
    .replace(/([a-z0-9])([A-Z])/g, '$1_$2')
    .replace(/([A-Z]+)([A-Z][a-z])/g, '$1_$2')       // HTTPServer → HTTP_Server
    .toLowerCase()
}
console.log(toSnake('HTTPServer'))       // http_server（表命中）
console.log(toSnake('parseUserName'))    // parse_user_name

// ④ 布尔用前缀，集合用复数 —— 提升可读性
function describe(order) {
  return {
    isPaid:    order.status === 'paid',   // 布尔一律 is/has/can/should
    hasItems:  order.items.length > 0,
    items:     order.items,               // 集合用复数
    firstItem: order.items[0],            // 单个用单数
  }
}

// ⑤ 避免零信息量命名
const BAD  = { data: 1, info: 2, obj: 3, temp: 4 }
const GOOD = { userProfile: 1, requestHeaders: 2, httpResponse: 3, retryCount: 4 }

// ⑥ 跨语言边界显式转换（API 层 camelCase ↔ DB 层 snake_case）
const toCamel = s => s.replace(/_([a-z])/g, (_, c) => c.toUpperCase())
const toSnakeKey = s => s.replace(/([a-z0-9])([A-Z])/g, '$1_$2').toLowerCase()
console.log(toCamel('user_id'))          // userId
console.log(toSnakeKey('userId'))        // user_id