Understanding V8’s Bytecode

v8-bytecode.js

// https://medium.com/dailyjs/understanding-v8s-bytecode-317d46c94775
// node --print-bytecode --print-bytecode-filter=ZXC v8-bytecode.js
function ZXC() {
  var A = 0;
  let B = 0;
  const C = 0;
  
  const O = {};
  
  const N = 9;
}
ZXC();

/*
[generating bytecode for function: ZXC]
Parameter count 1
Frame size 48
  136 E> 0x3c901c14e20e @    0 : 91                StackCheck 
  
  151 S> 0x3c901c14e20f @    1 : 02                LdaZero 
         0x3c901c14e210 @    2 : 1e fa             Star r0
         
  164 S> 0x3c901c14e212 @    4 : 02                LdaZero 
         0x3c901c14e213 @    5 : 1e f9             Star r1
         
  179 S> 0x3c901c14e215 @    7 : 02                LdaZero 
         0x3c901c14e216 @    8 : 1e f8             Star r2
         
  197 S> 0x3c901c14e218 @   10 : 6d 00 03 29 f5    CreateObjectLiteral [0], [3], #41, r5
         0x3c901c14e21d @   15 : 1f f5 f7          Mov r5, r3
         
  216 S> 0x3c901c14e220 @   18 : 03 09             LdaSmi [9]
         0x3c901c14e222 @   20 : 1e f6             Star r4
         
         0x3c901c14e224 @   22 : 04                LdaUndefined 
  219 S> 0x3c901c14e225 @   23 : 95                Return 
Constant pool (size = 1) // because of object, no matter var/let/const
Handler Table (size = 16)
 */