electron-log/src/renderer/lib/transports/console.js

Just a simple logging module for your Electron application

'use strict';

/* eslint-disable no-console */

const { transform } = require('../../../core/transforms/transform');

module.exports = consoleTransportRendererFactory;

const consoleMethods = {
  error: console.error,
  warn: console.warn,
  info: console.info,
  verbose: console.info,
  debug: console.debug,
  silly: console.debug,
  log: console.log,
};

function consoleTransportRendererFactory(logger) {
  return Object.assign(transport, {
    format: '{h}:{i}:{s}.{ms}{scope} › {text}',
    transforms: [formatDataFn],

    writeFn({ message: { level, data } }) {
      const consoleLogFn = consoleMethods[level] || consoleMethods.info;

      // make an empty call stack
      setTimeout(() => consoleLogFn(...data));
    },
  });

  function transport(message) {
    transport.writeFn({
      message: { ...message, data: transform({ logger, message, transport }) },
    });
  }
}

function formatDataFn({
  data = [],
  logger = {},
  message = {},
  transport = {},
}) {
  if (typeof transport.format === 'function') {
    return transport.format({
      data,
      level: message?.level || 'info',
      logger,
      message,
      transport,
    });
  }

  if (typeof transport.format !== 'string') {
    return data;
  }

  data.unshift(transport.format);

  // Concatenate the first two data items to support printf-like templates
  if (typeof data[1] === 'string' && data[1].match(/%[1cdfiOos]/)) {
    data = [`${data[0]}${data[1]}`, ...data.slice(2)];
  }

  const date = message.date || new Date();
  data[0] = data[0]
    .replace(/\{(\w+)}/g, (substring, name) => {
      switch (name) {
        case 'level': return message.level;
        case 'logId': return message.logId;
        case 'scope': {
          const scope = message.scope || logger.scope?.defaultLabel;
          return scope ? ` (${scope})` : '';
        }
        case 'text': return '';

        case 'y': return date.getFullYear().toString(10);
        case 'm': return (date.getMonth() + 1).toString(10)
          .padStart(2, '0');
        case 'd': return date.getDate().toString(10).padStart(2, '0');
        case 'h': return date.getHours().toString(10).padStart(2, '0');
        case 'i': return date.getMinutes().toString(10).padStart(2, '0');
        case 's': return date.getSeconds().toString(10).padStart(2, '0');
        case 'ms': return date.getMilliseconds().toString(10)
          .padStart(3, '0');
        case 'iso': return date.toISOString();

        default: return message.variables?.[name] || substring;
      }
    })
    .trim();

  return data;
}