debug-trace.js

/**
 * Module dependencies.
 */

var callsite = require('callsite')
  , tty = require('tty')
  , isatty = Boolean(tty.isatty(2) && process.stdout.getWindowSize)
  , defaultColors = { log: '90', error: '91', warn: '93', info: '96', trace: '90' }

/**
* Store custom options
*
* @param {Object} options
* @api public
*/

module.exports = function debugTrace(options) {
  options = options || {};
  console.traceOptions = console.traceOptions || {};
  console.traceOptions.cwd = options.cwd || process.cwd() + '/';
  console.traceOptions.colors = typeof options.colors !== 'undefined' ? options.colors : true;
  console.traceOptions.always = typeof options.always !== 'undefined' ? options.always : true;
  console.traceOptions.right = typeof options.right !== 'undefined' ? options.right : false;
  if (typeof options.overwriteDebugLog === 'undefined' || options.overwriteDebugLog) overwriteDebugLog(options.overwriteDebugLog)
  if (typeof options.patchOutput === 'undefined' || options.patchOutput) patchOutput()
}

function overwriteDebugLog(debugLog) {
  debugLog = typeof debugLog === 'function' ? debugLog : console.log;
  try {
    var Debug = require('debug');
    Debug.log = function log() {
      return debugLog.apply(debugLog, arguments);
    };
  } catch (error) {
    console.log('debug module is not installed');
  }
}

function patchOutput() {
  var stdout = process.stdout.write;
  var stderr = process.stderr.write;
  process.stdout.write = function write() {
    var stack = callsite();
    var trace = stack[1];
    if (trace.getFunctionName() === 'log') {
      var args = [].slice.call(arguments);
      if (typeof args[args.length - 1] === 'string') args[args.length - 1] = args[args.length - 1].replace(/\n$/g, '');
      return console.log.apply(console.log, args);
    }
    return stdout.apply(process.stdout, arguments)
  }
  process.stderr.write = function write() {
    var stack = callsite();
    var trace = stack[1];
    if (trace.getFunctionName() === 'log') {
      var args = [].slice.call(arguments);
      if (typeof args[args.length - 1] === 'string') args[args.length - 1] = args[args.length - 1].replace(/\n$/g, '');
      return console.log.apply(console.log, args);
    }
    return stderr.apply(process.stderr, arguments)
  }
}

/**
* Overrides the console methods.
*/

;['error', 'log', 'info', 'warn', 'trace'].forEach(function (name) {
  var fn = console[name];
  console[name] = function () {
    var args = arguments;
    if (console._trace || console.traceOptions.always) {
      if (args.length === 1) args = ['', args[0]];
      if (Buffer.isBuffer(args[0])) {
        args[0] = args[0].inspect()
      } else if (typeof args[0] === 'object') {
        args[0] = JSON.stringify(args[0], null, '  ');
      }
      var pad = (args[0] && !console.traceOptions.right || !isatty ? ' ' : '');
      // when using the debug module: dig one level deeper in the stack
      var stack = callsite();
      var trace = stack[1];
      if (stack.length > 2 && trace.getFunctionName() === 'log') {
        trace = stack[3];
        trace.debug = true;
      }
      if (stack.length > 3 && trace.getFunctionName() === 'write') {
        trace = stack[4];
        trace.debug = true;
      }
      trace.debug = trace.debug || false;
      args[0] = console.traceFormat(trace, name) + pad + args[0];
    }
    console._trace = false;
    return fn.apply(this, args);
  }
});

/**
* Overridable formatting function.
*
* @param {CallSite}
* @param {String} calling method
* @api public
*/

console.traceFormat = function (call, method) {
  call.filename = call.getFileName().replace(console.traceOptions.cwd, '');
  call.method = method;
  call.functionName = call.getFunctionName() || 'anonymous'
  call.getDate = function getDate() {
    return new Date().toISOString().replace('T', ' ').replace('Z', '');
  }

  var str = console.format(call);
  var color = '99';

  if (!isatty) {
    return str;
  }

  if (console.traceOptions.colors !== false) {
    if (console.traceOptions.colors === undefined || console.traceOptions.colors[method] === undefined) {
      color = defaultColors[method];
    } else {
      color = console.traceOptions.colors[method];
    }
  }

  if (console.traceOptions.right) {
    var rowWidth = process.stdout.getWindowSize()[0];
    return '\033[s' + // save current position
      '\033[' + rowWidth + 'D' + // move to the start of the line
      '\033[' + (rowWidth - str.length) + 'C' + // align right
      '\033[' + color + 'm' + str + '\033[39m' +
      '\033[u'; // restore current position
  } else {
    return '\033[' + color + 'm' + str + '\033[39m';
  }
}


/**
* Overridable string formatting function.
*
* @param {CallSite} CallSite Object pimped with additional properties.
* @api public
*/
console.format = function (c) {
  return c.getDate() + ": [" + c.filename + ":" + c.getLineNumber() + "] " + c.functionName;
};

/**
* Adds trace getter to the `console` object.
*
* @api public
*/

function getter() {
  this._trace = true;
  return this;
}

Object.defineProperty(console, 't', { get: getter });
Object.defineProperty(console, 'traced', { get: getter });