Easy rounding with Javascript round() wrapper

Really simple method to easily round with javascript:
function round (number, fractionalDigits) {
    "use strict";
    if (!number) {
        return; 
    }
    var multiplicator = 1;
    while (fractionalDigits--) {
        multiplicator *= 10;
    }
    return Math.round(number * multiplicator) / multiplicator;
}

Just pass in the number to round and the number of fractionalDigits you'd like to keep, like:
round(95.12345, 2); will return 95.12
round(95.54555, 4); will return 95.55

If you omit the last param, you'll get no fractionalDigit, like:
round(95.12345); will return 95
round(95.50000); will return 96

One last call: Don't use it as is, create a namespace for it to reside in! 


Or append it to Number, then you can remove the number param. ;)
Number.prototype.round = function(fractionalDigits) {
    "use strict";
    var multiplicator = 1; 
    while (fractionalDigits--) { 
        multiplicator *= 10; 
    } 
    return Math.round(this * multiplicator) / multiplicator;
}

Call it like:
var number = 8.12345;
number.round(2); will return 8.12


Have fun! 

No need for temporary variable (Javascript)

Assume you have a function, and that function has a param (called 'config' herein) which may be a string or an object. Inside your function, you check for the type and if it's a string, you want to make this strings value a property of your object.

My first, fast approach was this one:

var url = config;

config  = {};

config.videoLink = url;

My second approach looked like this:

var url = config;

config  = {videoLink: url};

I thought about what's happening in those statements and realized that the temporary variable 'url' is not needed, because javascript is executing the assignement from right to left, means I can override 'config' with an object that keeps the original value of config as a property. See this third & final approach:

config = {videoHash: config};

So Javascript builds the object, assigns the value of config (string) to videoHash and assigns this object to config, which now is a object as desired.

setTimeout() && setInterval() scope problem solver

This is so handy from time to time:

setInterval(
    function () {
        var myVar = document.getElementById("givenID");
        setTimeout(
            function() {
                // myVar is available because the inner closure 
                // gets the outer closures scope
                myVar.innerHTML = "Junk";
        },2000);
    }, 10000);

Source: Stackoverflow

Sencha Touch 1.1 - Adding a record and removing it doesn't work

I did the following and it worked well:

Add an entry - reload the app - delete that entry

I did the following and it didn't work:

Add an entry - delete that entry

Why?

I started to debug both cases paralelly. In both cases I found the new record in the object that is used to determine what has to be done, but for some strange reason in the case of adding and directly deleting that entry Sencha Touch doesn't find the entry. 

What I did is really simple: After running the store.remove(record) method I check if there's a record in the store.removed property. If not, I add that record manually. You can as well fully remove the store.remove(record) method call and write the record directly into the property. It's up to you.

After you did that you just need to call store.destroy() to remove the record.

Sencha Touch 1.1 - CRUD actions & callbacks via REST proxy

CRUD actions
Methods without value param (update, destroy):
store.update({
    callback: function(answer, object, success) {
        if (success) { ... }
    }
});

store.destroy({
    callback: function(answer, object, success) {
        if (success) { ... }
    }
});


Methods with value param (create, load):
store.create(values, {
    callback: function(answer, object, success) {
        if (success) { ... }
    }
});

store.load({
    callback: function(answer, object, success) {
        if (success) { ... }
    }
});


CRUD action executes only once?
If you can run some of these functions once and after that no XHR is made, it may be because you encountered this bug: Bug @ Sencha Forum

I solved this bug by setting store.snapshot to false, so the function that engages the XHR is no longer looking for changes in the snapshot but in the store object.

All Methods from a Javascript Object

I wrote that little helper because webdeveloper toolbar didn't show all methods to me. Maybe it's useful for you too.

https://gist.github.com/1441816

console.log & debug flag?

Instead of checking the DEBUG flag everytime you need a debug info, like this:

    if (DEBUG) {
        console.log("my debug output");
    }

you can just check the DEBUG flag once and disable the console.log function, like this:

    if (DEBUG === false) {
        console = {
            log: function() {}
        };
    }

This enables you to simply call:

    console.log("my debug output")

in your application. If DEBUG is true, you'll get your output. If DEBUG is false, console.log() will be called but is an empty function and thus will produce no output / error.

JS Module Pattern

var someModule = (function(){
//private attributes
  var privateVar = 5;

  //private methods
  var privateMethod = function(){
  return 'Private Test';
  };

  return {
    //public attributes
    publicVar: 10,
    //public methods
    publicMethod: function(){
      return ' Followed By Public Test ';
    },

    //let's access the private members
    getData: function(){
      return privateMethod() + this.publicMethod() + privateVar;
    }
  }
})(); //the parens here cause the anonymous function to execute and return
        
someModule.getData();
SOURCE: http://addyosmani.com/resources/essentialjsdesignpatterns/book/

Nyromodal Wiki Startpage is defective, use this older version instead

http://bit.ly/qUra4h

Nyromodal strips / removes script tag on ajax / xhr load

Got me some time to get 'round this, here's the solution:

"If you need to use an external JavaScript content, you could add the attribute rel="forceLoad" to the script tag and nyroModal will load it during the opening modal."


"If you want to use a script which need the content to be visible (many jQuery UI script for instance) you could add the setting rev="shown" to the inline or external script tag to execute it juste before the endShowContent callback."

Source: http://bit.ly/oJ8AeD

Writing a Chrome Extension - HTML + JS

http://geeknizer.com/google-chrome-4-extensions-how-to-create-twitter-client-download-tutorial/

On event.preventDefault() error messages in IE 8 (9? 7? 6?)

If checking for event.preventDefault() you get error messages in IE.

A better way is to check for the existence of event.returnValue (which is IEs preventDefault()) and if it doesn't exist you know that you're not on IE.

if (event.returnValue) {
    // this is IE
    event.returnValue = false;
} else {
    // this is Chrome, Firefox, Safari etc.
    event.preventDefault();
}

Javascript OOP Cheatsheet

var MyClass = function() {

    // self to get "this" in private / global / anonymous methods
    var self = this;

    // public var
    this.publicVar = 'public';
    // private var
    var privateVar = 'private';

    // public method
    this.publicMethod = function() {}
    // private method
    function privateMethod() {}
    // global method
    globalMethod = function() {}

}