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// Copyright 2019-2020 Yusuke Sakurai. All rights reserved. MIT license.import {  cyan,  gray,  red,  yellow,} from "./vendor/https/deno.land/std/fmt/colors.ts";import { sprintf } from "./vendor/https/deno.land/std/fmt/printf.ts";export enum Loglevel {  DEBUG,  INFO,  WARN,  ERROR,  NONE,}
export interface Logger {  (level: Loglevel, msg: string, ...args: any[]): void;}let logLevel = Loglevel.INFO;export function setLevel(level: Loglevel) {  logLevel = level;}const kPrefixMap = new Map<Loglevel, string>([  [Loglevel.INFO, "I"],  [Loglevel.DEBUG, "D"],  [Loglevel.WARN, "W"],  [Loglevel.ERROR, "E"],]);interface ColorFunc {  (msg: string): string;}const plain: ColorFunc = (msg) => msg;const kColorFuncMap = new Map<Loglevel, ColorFunc>([  [Loglevel.DEBUG, gray],  [Loglevel.INFO, cyan],  [Loglevel.WARN, yellow],  [Loglevel.ERROR, red],]);export interface NamedLogger {  debug(msg: string, ...args: any[]): void;  info(msg: string, ...args: any[]): void;  warn(msg: string, ...args: any[]): void;  error(msg: string, ...args: any[]): void;}
export function createLogger(  handler: Logger = (level, msg, ...args) => console.log(msg, ...args),  {    prefixMap = kPrefixMap,    prefixColorMap = kColorFuncMap,    prefixFmt = "%s[%s] %s",    noColor = false,  }: {    prefixFmt?: string;    prefixMap?: Map<Loglevel, string>;    prefixColorMap?: Map<Loglevel, ColorFunc>;    noColor?: boolean;  } = {},): Logger {  return function log(level: Loglevel, msg: string, ...args: any[]) {    if (level < logLevel) return;    const prefix = prefixMap.get(level) || "D";    let color = prefixColorMap.get(level);    if (noColor || !color) {      color = plain;    }    // [INFO] namespace msg    const now = new Date();    if (logLevel <= level) {      handler(        level,        sprintf(prefixFmt, color(prefix), now.toISOString(), msg),        ...args,      );    }  };}
export function namedLogger(  namespace: string,  handler: Logger = createLogger(),): NamedLogger {  const wrap = (msg: string) => `${namespace} ${msg}`;  return {    debug(msg: string, ...args: any[]) {      handler(Loglevel.DEBUG, wrap(msg), ...args);    },    error(msg: string, ...args: any[]) {      handler(Loglevel.ERROR, wrap(msg), ...args);    },    info(msg: string, ...args: any[]) {      handler(Loglevel.INFO, wrap(msg), ...args);    },    warn(msg: string, ...args: any[]) {      handler(Loglevel.ERROR, wrap(msg), ...args);    },  };}