Execution context in detail.

We saw in the last chapter when a new execution context is created, let's see now what happen in this execution context. An execution context contains three properties:

• The variable object who store functions.
• The scope chain who store variables and parents variables.
• And the this variable. When a function is called a new execution context is put on top of the execution stack, inside this one there are two phases.

Creation phase

During this phase we define the properties of the execution context which we already defined above, the first one is

Variable object

• First, the argument object is created containing all the arguments that were passed into the function.
• Second, the code is scanned for functions declarations and for each function a property is created in the variable object, pointing to the function.
• Third, the code is scanned for variable declarations and for each variable a property is created in the variable object and set to undefined.

Scope chain

This section deserve an entire lesson so check this links to understand how scope chain works.

This variable

You can find more details to this section by checking this file this keyword

Execution phase

During this phase the code is executed line by line.

Current errors

This is a list of the main errors that you can meet when you use execution context in detail:

Note: I'm not a wizard there is maybe some issue that you notice above so fell free to open an issue in the github repo if you find a new error not mentioned above.