Web Advanced-04 Low-level processing of browser stack memory

Compiler (parsing the code into a structure that the browser can understand): lexical analysis / AST abstract syntax tree / constructing code that the browser can execute

Engine (V8 engine, webkit kernel): Variable promotion / Scope, closure / Variable object / Stack memory / GO, VO, AO, EC, ECStack

let a = { n : 10 };
let b = a;
b.n = 20;
console.log(a.n);   //20

let a = { n : 10 };
let b = a;
b = { n : 20 };
console.log(a.n);   //10

Engine processing flow chart:

Interview questions:

let a = { n : 10 };
let b = a;
 b.m = b = {n: 20 }; //that is, b.m = {n: 20} b = {n: 20}
console.log(a); //{n:10,m:{n:20}}
console.log(b); //{n:20}

let x = [12,23];
function fn(y){ //that is, y = x;
    y[0] = 100;
    y = [100];
    y[1] = 200;
    console.log(y); // [100,200]
}
fn(x); 
console.log(x); // [100,23]

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