Try the [JavaScript **in** operator][1].

    if (&#39;key&#39; in myObj)

And the inverse.

    if (!(&#39;key&#39; in myObj))

**Be careful!** The `in` operator matches all object keys, including those in the object&#39;s prototype chain.

Use `myObj.hasOwnProperty(&#39;key&#39;)` to check an object&#39;s own keys and will only return `true` if `key` is available on `myObj` directly:

    myObj.hasOwnProperty(&#39;key&#39;)

Unless you have a specific reason to use the `in` operator, using `myObj.hasOwnProperty(&#39;key&#39;)` produces the result most code is looking for.


  [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/in

You should use [`hasOwnProperty`][1]. For example:

    myObj.hasOwnProperty(&#39;myKey&#39;);


  [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty

**Note:** If you are using ESLint, the above may give you an error for violating the [no-prototype-builtins](https://eslint.org/docs/rules/no-prototype-builtins) rule, in that case the workaround is as below:

    Object.prototype.hasOwnProperty.call(myObj, &#39;myKey&#39;);


I&#39;ve been using the idiom below for some time now. And it seems to be the most wide-spread, at least on the sites I&#39;ve visited.

Is there a better/different way to read a file into a string in Java?

    private String readFile(String file) throws IOException {
        BufferedReader reader = new BufferedReader(new FileReader (file));
        String         line = null;
        StringBuilder  stringBuilder = new StringBuilder();
        String         ls = System.getProperty(&quot;line.separator&quot;);

        try {
            while((line = reader.readLine()) != null) {
                stringBuilder.append(line);
                stringBuilder.append(ls);
            }

            return stringBuilder.toString();
        } finally {
            reader.close();
        }
    }


How do I create a Java string from the contents of a file?

Why would someone prefer either the [Lodash][1] or [Underscore.js][2] utility library over the other?

Lodash seems to be a drop-in replacement for underscore, the latter having been around longer.

I think both are brilliant, but I do not know enough about how they work to make an educated comparison, and I would like to know more about the differences.

  [1]: http://lodash.com/
  [2]: http://underscorejs.org/




Differences between Lodash and Underscore.js

Which is the right thing to do?

    if (myObj[&#39;key&#39;] == undefined)

or

    if (myObj[&#39;key&#39;] == null)

or

    if (myObj[&#39;key&#39;])


How do I check if an object has a key in JavaScript?

Which is the right thing to do?
<pre><code class="hljs language-css">if (myObj['key'] == undefined)
</code></pre>
or
<pre><code class="hljs language-csharp">if (myObj['key'] == null)
</code></pre>
or
<pre><code class="hljs language-css">if (myObj['key'])
</code></pre>

I want to send a datetime.datetime object in serialized form from Python using [JSON][1] and de-serialize in JavaScript using JSON. What is the best way to do this?


  [1]: http://en.wikipedia.org/wiki/JSON

JSON datetime between Python and JavaScript

What is the best way(s) to fake function overloading in Javascript? 

I know it is not possible to overload functions in Javascript as in other languages. 
If I needed a function with two uses `foo(x)` and `foo(x,y,z)` which is the best / preferred way:

 1. Using different names in the first place
 2. Using optional arguments like `y = y || &#39;default&#39;`
 3. Using number of arguments
 4. Checking types of arguments
 5. Or how?

Function overloading in Javascript - Best practices

Actually I am trying to move some box alternatively with in another box. I made it work, but both the blocks do not interrupt each other. What should I do? How can I make the blocks cross each other? I try using style:position, but it is not working.

Here is the code I have been using:

    &lt;marquee direction=&quot;down&quot; behavior=&quot;alternate&quot; scrollAmount=10 style=&quot;border:2px solid blue;&quot;&gt;
      &lt;marquee behavior=&quot;alternate&quot; scrollAmount=50 &gt;
        &lt;img src=&quot;img1.JPG&quot;&gt;
      &lt;/marquee&gt;
      &lt;marquee behavior=&quot;alternate&quot; scrollAmount=10 &gt;
        &lt;img src=&quot;img1.JPG&quot;&gt;
      &lt;/marquee&gt;
    &lt;/marquee&gt;

What am I doing wrong?


Nested and multiple &lt;marquee&gt; troubles

I have a pretty good understanding of Javascript, except that I can&#39;t figure out a nice way to set the &quot;this&quot; variable.  Consider:

    var myFunction = function(){
        alert(this.foo_variable);
    }
	
    var someObj = document.body; //using body as example object
    someObj.foo_variable = &quot;hi&quot;; //set foo_variable so it alerts

    var old_fn = someObj.fn;   //store old value
    someObj.fn = myFunction;   //bind to someObj so &quot;this&quot; keyword works
    someObj.fn();              
    someObj.fn = old_fn;       //restore old value

Is there a way to do this without the last 4 lines?  It&#39;s rather annoying...  I&#39;ve tried   binding an anonymous function, which I thought was beautiful and clever, but to no avail:
 
    var myFunction = function(){
        alert(this.foo_variable);
    }
	
    var someObj = document.body;        //using body as example object
    someObj.foo_variable = &quot;hi&quot;;        //set foo_variable so it alerts
    someObj.(function(){ fn(); })();    //fail.

Obviously, passing the variable into myFunction is an option... but that&#39;s not the point of this question.

Thanks.

Set &quot;this&quot; variable easily?

Please advise how to pass parameters into a function called using `setInterval`.

My example `setInterval(funca(10,3), 500);` is incorrect. 

Pass parameters in setInterval function

We have two PHP5 objects and would like to merge the content of one into the second. There are no notion of subclasses between them so the solutions described in the following topic cannot apply.

[How do you copy a PHP object into a different object type][1]


  [1]: https://stackoverflow.com/questions/119281/how-do-you-copy-a-php-object-into-a-different-object-type

    //We have this:
    $objectA-&gt;a;
    $objectA-&gt;b;
    $objectB-&gt;c;
    $objectB-&gt;d;
    
    //We want the easiest way to get:
    $objectC-&gt;a;
    $objectC-&gt;b;
    $objectC-&gt;c;
    $objectC-&gt;d;

**Remarks:**

 - These are objects, not classes.
 - The objects contain quite a lot of fields so a **foreach** would be quite slow.
 - So far we consider transforming objects A and B into arrays then merging them using **array_merge()** before re-transforming into an object but we can&#39;t say we are proud if this.



What is the best method to merge two PHP objects?

I&#39;m using jQuery and I want to check the existence of an element in my page. I have written following code, but it&#39;s not working:

    if($(&quot;#btext&quot; + i) != null) {
        //alert($(&quot;#btext&quot; + i).text());
    	$(&quot;#btext&quot; + i).text(&quot;Branch &quot; + i);
    }

How do I check the existence of the element?

How to check null objects in jQuery

Is it like...

    var obj = new Object();
    
    obj.function1 = function(){
        //code
    }

or something like that?


How do you create a method for a custom object in JavaScript?

This is what I&#39;ve come up with as a method on a class inherited by many of my other classes. The idea is that it allows the simple comparison between properties of Objects of the same Type.

Now, this does work - but in the interest of improving the quality of my code I thought I&#39;d throw it out for scrutiny. How can it be better/more efficient/etc.?



    /// &lt;summary&gt;
    /// Compare property values (as strings)
    /// &lt;/summary&gt;
    /// &lt;param name=&quot;obj&quot;&gt;&lt;/param&gt;
    /// &lt;returns&gt;&lt;/returns&gt;
    public bool PropertiesEqual(object comparisonObject)
    {
        
        Type sourceType = this.GetType();
        Type destinationType = comparisonObject.GetType();

        if (sourceType == destinationType)
        {
            PropertyInfo[] sourceProperties = sourceType.GetProperties();
            foreach (PropertyInfo pi in sourceProperties)
            {
                if ((sourceType.GetProperty(pi.Name).GetValue(this, null) == null &amp;&amp; destinationType.GetProperty(pi.Name).GetValue(comparisonObject, null) == null))
                {
                    // if both are null, don&#39;t try to compare  (throws exception)
                }
                else if (!(sourceType.GetProperty(pi.Name).GetValue(this, null).ToString() == destinationType.GetProperty(pi.Name).GetValue(comparisonObject, null).ToString()))
                {
                    // only need one property to be different to fail Equals.
                    return false;
                }
            }
        }
        else
        {
            throw new ArgumentException(&quot;Comparison object must be of the same type.&quot;,&quot;comparisonObject&quot;);
        }

        return true;
    }

Comparing object properties in c#

The question is simple: How do you load custom `UITableViewCell` from Xib files? Doing so allows you to use Interface Builder to design your cells. The answer apparently is not simple due to memory managment issues. [This thread][1] mentions the issue and suggests a solution, but is pre NDA-release and lacks code. Here&#39;s a [long thread][2] that discusses the issue without providing a definitive answer. 

Here&#39;s some code I&#39;ve used:

    static NSString *CellIdentifier = @&quot;MyCellIdentifier&quot;;
    
    MyCell *cell = (MyCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
    	NSArray *nib = [[NSBundle mainBundle] loadNibNamed:CellIdentifier owner:self options:nil];
    	cell = (MyCell *)[nib objectAtIndex:0];
    }

To use this code, create MyCell.m/.h, a new subclass of `UITableViewCell` and add `IBOutlets` for the components you want. Then create a new &quot;Empty XIB&quot; file. Open the Xib file in IB, add a `UITableViewCell` object, set its identifier to &quot;MyCellIdentifier&quot;, and set its class to MyCell and add your components. Finally, connect the `IBOutlets` to the components. Note that we did not set the File&#39;s Owner in IB.

Other methods advocate setting the File&#39;s Owner and warn of memory leaks if the Xib is not loaded via an additional factory class. I tested the above under Instruments/Leaks and saw no memory leaks. 

So what&#39;s the canonical way to load cells from Xibs? Do we set File&#39;s Owner? Do we need a factory? If so, what&#39;s the code for the factory look like? If there are multiple solutions, let&#39;s clarify the pros and cons of each of them...

  [1]: https://stackoverflow.com/questions/134575/using-interface-builder-for-uitableviews
  [2]: http://discussions.apple.com/thread.jspa?messageID=8040526&amp;tstart=0

Content Type	Original Author	Original Content on Stackoverflow
Question	kevin	View Question on Stackoverflow
Solution 1 - Javascript	ForYourOwnGood	View Answer on Stackoverflow
Solution 2 - Javascript	typeoneerror	View Answer on Stackoverflow

How do I check if an object has a key in JavaScript?

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Solution 2 - Javascript

Differences between Lodash and Underscore.js

How do I create a Java string from the contents of a file?

Attributions