neo-blessed/lib/widgets/log.js

/**
 * log.js - log element for blessed
 * Copyright (c) 2013-2015, Christopher Jeffrey and contributors (MIT License).
 * https://github.com/chjj/blessed
 */

/**
 * Modules
 */

var util = require('util');

var nextTick = global.setImmediate || process.nextTick.bind(process);

var Node = require('./node');
var ScrollableText = require('./scrollabletext');

/**
 * Log
 */

function Log(options) {
  var self = this;

  if (!(this instanceof Node)) {
    return new Log(options);
  }

  options = options || {};

  ScrollableText.call(this, options);

  this.scrollback = options.scrollback != null
    ? options.scrollback
    : Infinity;
  this.scrollOnInput = options.scrollOnInput;

  this.on('set content', function() {
    if (!self._userScrolled || self.scrollOnInput) {
      nextTick(function() {
        self.setScrollPerc(100);
        self._userScrolled = false;
        self.screen.render();
      });
    }
  });
}

Log.prototype.__proto__ = ScrollableText.prototype;

Log.prototype.type = 'log';

Log.prototype.log =
Log.prototype.add = function() {
  var args = Array.prototype.slice.call(arguments);
  if (typeof args[0] === 'object') {
    args[0] = util.inspect(args[0], true, 20, true);
  }
  var text = util.format.apply(util, args);
  this.emit('log', text);
  var ret = this.pushLine(text);
  if (this._clines.fake.length > this.scrollback) {
    this.shiftLine(0, (this.scrollback / 3) | 0);
  }
  return ret;
};

Log.prototype._scroll = Log.prototype.scroll;
Log.prototype.scroll = function(offset, always) {
  if (offset === 0) return this._scroll(offset, always);
  this._userScrolled = true;
  var ret = this._scroll(offset, always);
  if (this.getScrollPerc() === 100) {
    this._userScrolled = false;
  }
  return ret;
};

/**
 * Expose
 */

module.exports = Log;