Tien Dung

[JavaScript] On Split text into unordered list.

2009-01-26T08:19:27-08:00

$(document).ready(function(){
  var resultsMax = 15;

  $.get('test-data.txt', function(textData){
    var lines = textData.split('\n').slice(0, resultsMax);
    
    $.each(lines, function(i, line){
      var terms = line.split('|');
      
      $('#tagcloud').append(
        '<li value="{index}"><a href="{url}" title="{title}">{title}</a></li>'.replace(/{(.+?)}/ig, function(raw, key) {
          return { 
            index : resultsMax - i, 
            url   : terms[3], 
            title : terms[0]
          }[ key ] || raw;
      }));      
    });
    
    $('#tagcloud').tagcloud();
  });
});

[JavaScript] On Check next option in select tag

2009-01-26T01:22:46-08:00

Simo refactoring is great. Just want to remove some code from checkNext function.

jQuery.fn.checkNext = function() {
  if (this.is(':selected')) {
    this.attr('selected', false);
    var next = this.is(':last-child') ? this.parent().children(':first') : this.next();
    next.attr('selected', true);
  }
}

[JavaScript] On Writing a loop to create a switch statment

2008-12-11T08:35:56-08:00

times = [
  null,
  '7:00AM ',
  '8:00AM ',
  '9:00AM ',
  '10:00AM ',
  '11:00AM ',
  '12:00PM ',
  '1:00PM ',
  '2:00PM ',
  '3:00PM ',
  '4:00PM ',
  '5:00PM ',
  '6:00PM ',
  '7:00PM '
]

var start_time = times[timeArray[0]] || 'error';

[C] On How to find max, min of three numbers?

2008-11-20T00:01:10-08:00

Hi Eineki, please explain how it works?

[C] How to find max, min of three numbers?

2008-11-18T12:33:54-08:00

I tried to use as less variables and less operators as possible.
Please help to make the code better.

int max = rand(); // or any init value
int min = rand(); // or any init value
int tmp = rand(); // or any init value

if (max < min) {
  if (tmp < min) {
    if (max < tmp) {
      tmp = max;
      max = min;
      min = tmp;
    } 
    else { // max < min && tmp < min && tmp <= max
      max = min;
      min = tmp;
    }
  } 
  else { // max < min && min <= tmp
    min = max;
    max = tmp;
  }
  
}
else { // min <= max
  if (tmp < min)
    min = tmp;

  else // min <= max && min <= tmp
  if (max < tmp)
    max = tmp;
}

[JavaScript] On Small Javascript Code

2008-10-06T22:23:45-07:00

You can't do ||= in JavaScript

function getAnchor(default) {
  default = default || 'news';
  return document.location.toString().split( '#' )[1] || default;
};

[JavaScript] On Toggle "Check all / Uncheck all" with jQuery

2008-10-06T22:19:01-07:00

Use true/false instead of using "on"/"off" for .mode
For .text() I think you can set it according to mode value

    Q("#toggler").click(function() {
        var mode = this.mode;
        this.mode = !mode;

        Q("form#the_form input.id").each(function(){
            this.checked = mode;
        }); 

        Q(this).text(mode ? 'check all' : 'uncheck all');
        return false;
    });

[JavaScript] On Small Javascript Code

2008-10-06T04:21:44-07:00

// Don't know why you need hash > 0 and page.length > 1
// In case you don't need those conditions
var page = document.location.toString().split("#")[1];
LoadURL(page || 'news')

// In case you need them
var parts = document.location.toString().split("#");
LoadURL((parts[0].length > 0 && parts[1].length > 1) ? parts[1] : 'news')

[Ruby] On Cleaner Ruby

2008-09-22T01:53:58-07:00

@Adam: cool refactoring :D

[Ruby] On Conditional Assignment

2008-09-22T01:27:00-07:00

temp variable based version using inject function.

def square(number)
  return number**2
end

biggest_square = [1,4,3,5].inject(0){ |max, base| (temp = square(base)) > max ? temp : max }

[Ruby] On Conditional Assignment

2008-09-22T00:01:09-07:00

Hi Daniel, can you ask Marc-Andre for comment on rating also. For me the reason or thinking behind a refactoring or a rating is more important than the code or the rating itself.

[Ruby] On Conditional Assignment

2008-09-21T22:31:37-07:00

Thanks Daniel. I found the last one is more readable and self-commenting. Nice refactoring.

[Ruby] On Conditional Assignment

2008-09-21T16:19:05-07:00

Don't know who vote 1 star for my "one line assignment using temp variable refactoring". Please tell me why you think it's bad. As I said the original code is perfect for me. That refactoring is in case your concern is lines of code.

[Ruby] On Conditional Assignment

2008-09-21T15:58:01-07:00

Refactor Amos King .max function version

def square(number)
  return number**2
end

biggest_square = [1,4,3,5].map{|base| square(base)}.max

[Ruby] On Conditional Assignment

2008-09-21T15:43:59-07:00

I prefer using temp variable for PERFORMANCE. For me, the # Alternative code is already clean and clear.

If your concern is lines of code. Here is one line assignment using temp variable refactoring.

def square(number)
  return number**2
end

biggest_square = 0

[1,4,3,5].each do |base|
  (temp = square(base)) > biggest_square && biggest_square = temp
end

[Ruby] On require_dependency

2008-09-21T00:13:30-07:00

Thanks for your help guys :)

I use require_dependency because it is used to reload source files on each request when in development mode.
http://wiki.rubyonrails.org/rails/pages/RequireDependency

Learn it from Rick's Beast forum
http://github.com/courtenay/altered_beast/tree/master/config/initializers/concerns.rb

[Ruby] On Cleaner Ruby

2008-09-20T23:57:43-07:00

Man, you made your code over complicated and ugly.

* Why you use class as a namespace?
* Why you create a function called xp_to_level and don't use it in your program?
* Why you don't reuse computation result from previous step?
* Why you name a function that no one can understand what does it mean without any comment? (what does xp stand for).

Here is an equivalent program that is faster, clearer and shorter.

def equate(level)
  (level + 300 * (2 ** (level / 7.0))).floor
end

x = 0
(1...100).each do |level|
  puts("level #{level}: #{(x/4).floor}")
  x = x + equate(level)
end

[Ruby] On Cleaner Ruby

2008-09-20T23:34:59-07:00

# Duplicated post, please help to delete

[Ruby] require_dependency

2008-09-18T01:08:56-07:00

Rails require_dependency usage

class Listing < ActiveRecord::Base
  require_dependency "listing/property_related"
  require_dependency "listing/price_related"
  require_dependency "listing/contact_related"
  require_dependency "listing/address_related"
  require_dependency "full_text_search/listing_config"
  ....
end

[JavaScript] On Color elements by state of matter at temperature

2008-09-16T06:44:54-07:00

or using eval(..)

function state_classes(updateall) {
    var value = display.value * 1, tempcolor;
    var element, state, 
        validations = {
          "Unknown" : "!boil[i] && !melt[i]", 
          "Gas"     : "value > boil[i]",
          "Liquid"  : "value > melt[i]", 
          "Solid"   : "true"
        };

    for (var i = 1; i <= 118; i++) {
        tempcolor = updateall;
        element = element_ids[i];
        
        for ( state in validations ) 
         if ( validations.hasOwnProperty(state) && 
              element.state !== state &&
              eval(validations[state]) )
         {
           tempcolor = true;
           element.state = state;
           break;
         }

        if (tempcolor) {
          if (wholetable.inverted)    
            element.style.backgroundColor = statecolors[1][element.state];
          else                        
            element.style.color = statecolors[0][element.state];
        }
    }
}

[JavaScript] On Color elements by state of matter at temperature

2008-09-16T00:52:57-07:00

function state_classes(updateall) {
    var value = display.value * 1, tempcolor;
    var element, state, states = ["Unknown", "Gas", "Liquid", "Solid"];
    for (var i = 1; i <= 118; i++) {
        tempcolor = updateall;
        element = element_ids[i];
        
        for (var j = 0; j < state.length; j++) {
           state = states[j];
           if (element.state !== state) {
             if ( (state === "Unknown" && !boil[i] && !melt[i]) ||
                  (state === "Gas"     && value > boil[i]) ||
                  (state === "Liquid"  && value > melt[i]) ||
                  (state === "Solid")
             {
                tempcolor = true;
                element.state = state;
                break;
             }
           }
        }        

        if (tempcolor) {
          if (wholetable.inverted)    
            element.style.backgroundColor = statecolors[1][element.state];
          else                        
            element.style.color = statecolors[0][element.state];
        }
    }
}

[JavaScript] On Setting focus after alert

2008-08-19T00:41:31-07:00

Hi Daniel,

I create a saveAndSet function to remove repetitions. Don't have time to test. Hope it work :)

function saveAndSet(obj, newValues) {
  var oldValues = {};
  for (var p in newValues) 
    if (newValues.hasOwnProperty(p)) {
      oldValues[p] = obj[p];
      obj[p] = newValues[p];
    } 
  return oldValues;
}

function msgFocus(msg, obj) {
    var oldValues = saveAndSet(obj, {onkeyup: null, onkeypress: null, onblur: null, onfocus: null });
        
    alert(msg);
        
    setTimeout(function() {
        obj.focus();
        saveAndSet(obj, oldValues);
    }, 50);
}

[Ruby] On showing records in Ascending or Descening order on click

2008-08-06T14:07:58-07:00

Hi DG,

1) We should not put model data (User model) in session because:
- Session is used to hold only the TEMPORARY data between a specific user and our web app.
- Session data should be kept as small as possible. For most of the case the user_id is enough.
- Model data is PERSISTENT data and should be consistent with all views (from different users).
- If we keep model data in session, each user will have a different copy of model data. It invalid the consistency.

2) We should not put model-related code in controller. We can move them to model.rb file to keep controller slim :)
Another benefit of putting logic code in model is that you can test code more easier.
You can "script/console" and try model's functions or write spec tests for them.

3) Don't afraid database queries will slow down the app. Finding & sorting are the jobs of database system.

Base on 3 points above I refactor your code as below.
I use param variable params[:order_by] to guide the controller to sort @users by age_ascending, age_descending and salary_ascending.
Urls will look like:
/users?
=> show all users ordered by age DESC

/users?order_by=age
=> show all user ordered by age ASC

/users?order_by=salary
=> show all user ordered by salary ASC

class UsersController < ApplicationController
  def index
    @users = find_all_and_order_by(params[:order_by])
  end
end


# user.rb
class User < ActiveRecord::Base
  named_scope :order_by_age_descending,   :order => "age DESC"
  named_scope :order_by_age_ascending,    :order => "age ASC"
  named_scope :order_by_salary_ascending, :order => "salary ASC"

  def self.find_all_and_order_by( field_name )
    case field_name
    when "age"
      User.order_by_age_ascending.all
    when "salary"
      User.order_by_salary_ascending.all
    default
      User.order_by_age_descending.all
    end
  end
end

# Now we can "script/console" and try User.find_all_and_order_by("age")

[JavaScript] On Handling Keyboard Shortcuts in JavaScript

2008-08-06T07:22:20-07:00

My final attempt :)

/**
 * http://www.openjs.com/scripts/events/keyboard_shortcuts/
 * Version : 2.01.B
 * By Binny V A
 * License : BSD
 *
 * Refactored by Nguyen Tien Dung ( http://free-and-happy.blogspot.com )
 */
window.shortcut = (function () {

  var defaultOptions = {
    type      : 'keydown',
    propagate : false,
    disable   : 'input textarea',
    target    : document,
    keycode   : false
  };

  // Work around for Shift key bug created by using lowercase
  // as a result the shift+num combinationnation was broken
  var shiftNums = {
    '`':'~',    '1':'!',    '2':'@',    '3':'#',  
    '4':'$',    '5':'%',    '6':'^',    '7':'&',    '8':'*',  
    '9':'(',    '0':')',    '-':'_',    '=':'+',    ';':':',  
    "'":'"',    ',':'<',    '.':'>',    '/':'?',   '\\':'|'
  };
	
  // Special Keys and their codes
  var specialKeys = {
    'escape'  :27,	'space'	:32,
    'return'  :13,	'enter'	:13,
    'pause'   :19,	'break'	:19,
    'insert'  :45,	'home'	:36, 
    'delete'  :46,      'end'   :35,

    'backspace'  :8,    'esc'         :27,    'tab'    :9,
    'scrolllock' :145,  'scroll_lock' :145,   'scroll' :145,
    'capslock'   :20,   'caps_lock'   :20,    'caps'   :20, 
    'numlock'    :144,  'num_lock'    :144,   'num'    :144,
    'pageup'     :33,   'page_up'     :33,    'pu'     :33,
    'pagedown'   :34,   'page_down'   :34,    'pd'     :34,

    'left':37,   'up':38,   'right':39,   'down':40,
    'f1':112,    'f2':113,   'f3' :114,    'f4' :115, 
    'f5':116,    'f6':117,   'f7' :118,    'f8' :119, 
    'f9':120,   'f10':121,   'f11':122,   'f12' :123
  };

  var modifierMapping = {
    ctrl   :'ctrl',     control :'ctrl',
    shift  :'shift',    alt     :'alt',
    option :'alt',      meta    :'meta'
  };
  
  var bindings = {};

  function triggeredInDisableTags(event, disableTags) {
    if (typeof disableTags !== 'string') return false; 

    var element = event.target || event.srcElement;
    if (element.nodeType === 3)
      element = element.parentNode;

    return (disableTags.toLowerCase().indexOf(element.tagName.toLowerCase()) >= 0) ? true : false;
  }
	
	
  function matching(combination, options, e) {
    var i, key, modifier;
    var want = {};
    var keys = combination.split('+');

    //Find Which key is pressed
    var code = e.keyCode || e.which;
    var char = { 188: ',', 190: '.' }[code] || String.fromCharCode(code).toLowerCase();

    var count = 0;
    for (i=0; i < keys.length; i++) {
      key = keys[i];
      modifier = modifierMapping[key];

      if (modifier) {
        want[modifier] = true;
        count++;
      } 
      else 
      if ( (key.length > 1 && specialKeys[key] === code) ||
           (options.keycode === code) || (char === key) || 
           (e.shiftKey && shiftNums[char] === key) ) 
        count++; 
    } // End for (..)
		
    return (
      keys.length  === count &&
      !!want.shift === !!e.shiftKey &&
      !!want.ctrl  === !!e.ctrlKey &&
      !!want.alt   === !!e.altKey &&
      !!want.meta  === !!e.metaKey
    );
  }

  // Return the function to be called at keypress
  function makeKeypressedFun( combination, callback, options ) {
    return function( e ) {
      e = e || window.event;

      if ( triggeredInDisableTags(e, options.disable) || 
           !matching(combination, options, e) ) return;

      callback(e);
      if( !options.propagate ) {
        e.stopPropagation && e.stopPropagation();
        e.preventDefault && e.preventDefault();
        e.cancelBubble = true;
        e.returnValue = false;
      }
    };
  }

	
return /*shotcut*/ {
  add: function(combination, callback, options) {
    options = options || {};

    for (var name in defaultOptions)
      if (!options.hasOwnProperty(name))
        options[name] = defaultOptions[name];
		
    var ele = options.target;

    if(typeof ele === 'string')
      ele = document.getElementById(ele);

    var func = makeKeypressedFun( combination, callback, options );
		
    bindings[combination.toLowerCase()] = {
      'callback' : func,
      'target'	 : ele,
      'event'    : options.type
    };

    //Attach the function with the event
    if (ele.addEventListener)
        ele.addEventListener(options.type, func, false); 
    else 
    if (ele.attachEvent)
        ele.attachEvent('on' + options.type, func); 
    else
      ele['on' + options.type] = func; 
  },

  //Remove the shortcut - just specify the shortcut and I will remove the binding
  remove: function(combination) {
    combination = combination.toLowerCase();
    var binding = bindings[combination];

    delete bindings[combination];

    if( !binding ) return;
		
    var type = binding.event;
    var ele = binding.target;
    var callback = binding.callback;

    if (ele.detachEvent)
        ele.detachEvent('on'+type, callback);
    else 
    if (ele.removeEventListener)
        ele.removeEventListener(type, callback, false);
    else
      ele['on'+type] = false;
  }	
};
})();

[Ruby] On two for loops cleanup?

2008-07-31T02:05:35-07:00

Shortest version :)

times -= events.map(&:datetime)