identifier: fancy word for label used to store anything(variable, function) in the memory.
JavaScript Principles
- Thread Of Execution: JS runs code line by line and uses memory to store variables value or function’s code.
- Execution Context: Each function when run will have its own execution context i.e it will have its own memory and thread of execution will run code and store relevant data inside that separate execution context. By default JS has global execution context.(Basically I think execution context is nothing but separate memory block for every function including global function).
- Call Stack: For thread of execution to keep track of which function is to be executed/ which execution context is being used, Call stack is used by JS.
// add notes of callback portion
Closure
Refers to concept where on function declaration, function definition being stored has access to all variables defined in its lexical scope. So during variable look up if variable is not present in the current function’s execution context, it first looks into the closure/backpack/closed over enviornment variable memory if variable is present. If present then that value is used. If not then variable is searched within calling context’s execution context i.e the function calling the current executing function. This lexical scope variables are stored in function’s [ [Scope] ] property
Asynchronous Javascript
Everything about event loop
OO JS
Everything about function, proto, prototype and new keyword