Ever wondered how the null coalescing operator || works in JavaScript?

For those who are wondering what exactly the null coalescing operator is, consider the following example:

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var a = null;
var b = a || 10;
console.log(b); // It will log 10

It is very probably that you already used such code in your programs. In the previous example, with the || operator we are practically set the number 10 to variable b, if the value inside variable a is null.

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How to fix the "Invalid tag value. This XML tag has an invalid value. Please fix it and resubmit." error when using the jekyll-sitemap gem.

After I installed the jekyll-sitemap gem on my Jekyll website and tried to register the generated sitemap in my Google webmaster account, I received from Google the following error:

Invalid tag value. This XML tag has an invalid value. Please fix it and resubmit.

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How to save time, mouse clicks and keystrokes by using keyboard-shortcuts in Visual Studio.

The following list contains my favorite keyboard-shortcuts in Visual Studio:

  • ctrl + K + C (Press Control, K and C): Comments out the selected lines of code.

  • ctrl + K + U (Press Control, K and U): Uncomments the selected commented lines of code.

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A list of helpful and often used commands of the npm package directory

The following list contains npm commands that I use practically every day while working with packages in my node.js projects:

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Create a drop-down list with custom options text and value in Angular

It is a common practice that the text of the options of a select drop-down box is a combination of a shortcut and it’s full text label.

For example consider the following array of JSON objects that a server might return:

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var countries = [
    {"shortcut": "DE", "label": "Germany"},
    {"shortcut": "GB", "label": "Great Britain"}
];
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