The most commonly used deep copy method

1. Recursion

function deepcopy(source) {
    
    
  if (!source) {
    
    
    return source
  }
  const sourceCopy = source instanceof Array ? [] : {
    
    }
  for (const item in source) {
    
    
    sourceCopy[item] =
      typeof source[item] === 'object' ? deepcopy(source[item]) : source[item]
  }
  return sourceCopy
}

2.JSON

const sourceCopy= JSON.parse(JSON.stringify(source))