gatsby-plugin-preload-fonts/prepare/logger.js

Gatsby plugin for preloading fonts per page

"use strict";

const chalk = require(`chalk`);
const readline = require(`readline`);
function noop() {}
const logLevels = {
  info: 0,
  debug: 1,
  warn: 2,
  error: 3,
  silent: 4
};
const getPrompt = (promptOrInfo, prompt) => {
  let info;
  if (!prompt) prompt = promptOrInfo;else info = promptOrInfo;
  if (info) console.log(info);
  return prompt;
};
module.exports = level => {
  let logLevel = logLevels[level];
  if (typeof logLevel === `undefined`) logLevel = logLevels.error;
  const question = prompt => new Promise(resolve => {
    const rl = readline.createInterface({
      input: process.stdin,
      output: process.stdout
    });
    rl.question(prompt, res => {
      rl.close();
      resolve(res);
    });
  });
  let adapter = console.log;
  const setAdapter = a => adapter = a;
  const resetAdapter = () => adapter = console.log;
  const prepend = tag => (...args) => adapter(tag, ...args);
  return {
    setAdapter,
    resetAdapter,
    newline: () => adapter(),
    info: logLevel <= logLevels.info ? prepend(chalk.white(`[info]`)) : noop,
    debug: logLevel <= logLevels.debug ? prepend(chalk.blue(`[debug]`)) : noop,
    warn: logLevel <= logLevels.warn ? prepend(chalk.yellow(`[warn]`)) : noop,
    error: logLevel <= logLevels.error ? prepend(chalk.red(`[error]`)) : noop,
    print: (...args) => adapter(...args),
    fatal: (...args) => adapter(...args) || process.exit(1),
    confirm: async (promptOrInfo, prompt) => {
      if (!process.stdout.isTTY) return false;
      prompt = getPrompt(promptOrInfo, prompt);
      let res = ``;
      while (!/(y|n|yes|no)/i.test(res)) {
        res = await question(`${prompt} ${chalk.bold(`[y/n]`)} `);
      }

      // print newline
      adapter();
      return /(y|yes)/i.test(res);
    }
  };
};