What happens during the memory creation phase in JavaScript?

During the memory creation phase, memory is allocated to variables and functions, with a special value of undefined being stored for variables and the entire code of functions being stored in memory.

What happens during the code execution phase in JavaScript?

During the code execution phase, the program runs through the code line by line, executing functions and calculations, and allocating memory and storing values in placeholders or identifiers.

What does function invocation mean in JavaScript?

Function invocation in JavaScript means executing a mini program, which creates a new execution context.

How does the call stack manage execution contexts in JavaScript?

The call stack in JavaScript manages the creation and deletion of execution contexts and maintains the order of their execution, acting as an execution context stack.

JavaScript Execution & Call Stack: Namaste JavaScript Ep. 2

Name: JavaScript Execution & Call Stack: Namaste JavaScript Ep. 2
Uploaded: 2023-04-17 13:59:43
Description: The video explains the two phases of creating an execution context in JavaScript, memory creation and code execution, and how the call stack manages the creation and deletion of these contexts.

This article is a summary of a YouTube video "How JavaScript Code is executed? ❤️& Call Stack | Namaste JavaScript Ep. 2" by Akshay Saini

TLDR The video explains the two phases of creating an execution context in JavaScript, memory creation and code execution, and how the call stack manages the creation and deletion of these contexts.

Key insights

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When running a JavaScript program, a global execution context is created with two components: the Memory Component and the Code Component.
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The memory creation phase in JavaScript code execution is critical and also known as the creation phase.
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Invoking a JavaScript function means running a mini program with its own execution context.
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Understanding the two components of an execution context - memory and code - is crucial in understanding how JavaScript code is executed.
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The return keyword in JavaScript tells the function to return control back to where it was invoked.
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When a function is executed, a new execution context is created and once the function is done executing, the execution context is deleted.
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Functions can be invoked multiple times, creating new execution contexts each time and repeating the same cycle of memory allocation and code execution.
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The call stack is a beautiful thing in JavaScript, as it handles everything to manage execution context creation, deletion, and control.

Q&A

What are the two phases of creating an execution context in JavaScript?

— The two phases of creating an execution context in JavaScript are memory creation and code execution.
What happens during the memory creation phase in JavaScript?

— During the memory creation phase, memory is allocated to variables and functions, with a special value of undefined being stored for variables and the entire code of functions being stored in memory.
What happens during the code execution phase in JavaScript?

— During the code execution phase, the program runs through the code line by line, executing functions and calculations, and allocating memory and storing values in placeholders or identifiers.
What does function invocation mean in JavaScript?

— Function invocation in JavaScript means executing a mini program, which creates a new execution context.
How does the call stack manage execution contexts in JavaScript?

— The call stack in JavaScript manages the creation and deletion of execution contexts and maintains the order of their execution, acting as an execution context stack.

Timestamped Summary

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00:00
An execution context in JavaScript has two components (memory and code) and is created in two phases.
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01:26
During the memory creation phase in JavaScript, variables and functions are allocated memory with undefined values and function code stored in memory.
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04:02
During code execution in JavaScript, functions are invoked and memory is allocated and stored in placeholders.
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07:34
During memory creation, variables and parameters are allocated, and during code execution, each line is executed with values being passed and calculated.
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10:56
The return keyword in a function sends the value of ans back to where the function was called.
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14:35
The function receives the argument 4 and stores the value 16 in the variable square4.
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16:03
The JavaScript program creates an execution context with memory and code components, executes the code, and returns the result.
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18:55
The JavaScript call stack manages the creation and deletion of execution contexts, with functions creating new contexts that are pushed onto the stack and popped off once executed.