58. JavaScript Execution Context 2: What is Scope Chain? What is Lexical Scoping? Nested Function?

#MissXing #JavaScript #javascript
In this video, I continued to explain Execution Context with 3 different demos. The demos are related to Scope Chain, Lexical Scoping in JavaScript.

[tenzl]

hi another question:

function b(m, n) {
function a(i, j) {
console.log(x);
}
a(5);
const x = 10;

}
const x = 20;
b(7, 8, 9);

why does a() get a reference error in this case? I know that function a() outer is referencing b() lexical environment and b() has x in the TDZ during a() execution. But wouldn't a() execution phase find that there is no x in it's parent's lexical environment (since it's in TDZ), thus it should search the global lexical environment where it's defined as 20 no?

[tenzl]

console.log() creates an execution context too right?