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dipakkr/ Secret

Created Oct 21, 2020
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In today's post, I am going to write about how javascript works. We will throw some light on terminologies like Execution context, function level execution context, function invoking, and threads.

**Do you know what happens behind the scene when you run a javascript code? **

Let's take an example of the below code snippet.

EC : Execution Context

When we run this code, here is what the Javascript engine does.

  • First, a Global Execution Context is going to be created.

  • Interpreter encounters call x(), and again a new EC is created for x.

  • Now the EC for x is created it will run the code line by line inside x.

  • Inside x, a new function call y() is invoked, it again creates an EC for y.

  • When y is finished running, it will back to EC of x, and variable t is assigned.

  • After x run is finished, it will be back to Global EC, and variable r is assigned.

  • Global EC finishes running and the program stops.

In tomorrow's blog, I will explain how the call stack works in Javascript. I would love to know your feedback on this blog.

Stay tuned - Follow me on Twitter

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