hono/deno_dist/middleware/logger/index.ts

import type { MiddlewareHandler } from '../../hono.ts'
import { getPathFromURL } from '../../utils/url.ts'

enum LogPrefix {
  Outgoing = '-->',
  Incoming = '<--',
  Error = 'xxx',
}

const humanize = (times: string[]) => {
  const [delimiter, separator] = [',', '.']

  const orderTimes = times.map((v) => v.replace(/(\d)(?=(\d\d\d)+(?!\d))/g, '$1' + delimiter))

  return orderTimes.join(separator)
}

const time = (start: number) => {
  const delta = Date.now() - start
  return humanize([delta < 1000 ? delta + 'ms' : Math.round(delta / 1000) + 's'])
}

const colorStatus = (status: number) => {
  const out: { [key: string]: string } = {
    7: `\x1b[35m${status}\x1b[0m`,
    5: `\x1b[31m${status}\x1b[0m`,
    4: `\x1b[33m${status}\x1b[0m`,
    3: `\x1b[36m${status}\x1b[0m`,
    2: `\x1b[32m${status}\x1b[0m`,
    1: `\x1b[32m${status}\x1b[0m`,
    0: `\x1b[33m${status}\x1b[0m`,
  }

  const calculateStatus = (status / 100) | 0

  return out[calculateStatus]
}

type PrintFunc = (str: string, ...rest: string[]) => void

function log(
  fn: PrintFunc,
  prefix: string,
  method: string,
  path: string,
  status: number = 0,
  elapsed?: string
) {
  const out =
    prefix === LogPrefix.Incoming
      ? `  ${prefix} ${method} ${path}`
      : `  ${prefix} ${method} ${path} ${colorStatus(status)} ${elapsed}`
  fn(out)
}

export const logger = (fn: PrintFunc = console.log): MiddlewareHandler => {
  return async (c, next) => {
    const { method } = c.req
    const path = getPathFromURL(c.req.url)

    log(fn, LogPrefix.Incoming, method, path)

    const start = Date.now()

    await next()

    log(fn, LogPrefix.Outgoing, method, path, c.res.status, time(start))
  }
}