I have learned some knowledge about the internal structure of the execution context before, and I probably know that there are variable objects VO/AO, this, scope chain Scope and other properties inside the execution context.
Today I read the about the execution context, which gives the data structures of the global execution context and the function execution context.
Global Execution Context = {
global object,
this: global object,
outer environment: null,
enviroment: {
// all the identifiers
variable,
function expression,
function declaration,
},
}
Execution Context = {
this: some value,
outer environment: outer lexcial environment,
enviroment: {
// all the identifiers
parameter,
arguments,
variable,
function expression,
function declaration,
},
} I have more questions:
- eviroment corresponds to variable objects in previous knowledge? The external pointer corresponds to Scope?
- according to previous knowledge, only the formal parameters of the function, the function declaration, and the variable declaration can enter the variable object. Why in function Execution Context, the function expression function expression also enters the enviroment, indicating that enviroment is not a variable object?
3. There are global object and enviroment, in Global Execution Context. According to reason, a global object is a global variable object, and there is no need to save two copies of the same thing, which proves that enviroment is not a variable object.
therefore, there are some doubts about the correctness of the original text.