JavaScript deep copy

deepCopy.js

function deepCopy(o) {
  // Cas de base
  if (typeof o !== 'object' || o === null || o instanceof RegExp || o instanceof Date) {
    return o
  }

  // Array
  if (Array.isArray(o) || o instanceof Int8Array || o instanceof Uint8Array || o instanceof Uint8ClampedArray || o instanceof Int16Array || o instanceof Uint16Array || o instanceof Int32Array || o instanceof Uint32Array || o instanceof Float32Array || o instanceof Float64Array || o instanceof BigInt64Array || o instanceof BigUint64Array) {
    return o.map(e => deepCopy(e))
  }

  // Object
  const finalObject = {}
  for (let k in o) {
    if (o.hasOwnProperty(k)) {
      finalObject[k] = deepCopy(o[k])
    }
  }
  return finalObject
}

example.js

function deepCopy(o) {
  // Cas de base
  if (typeof o !== 'object' || o === null || o instanceof RegExp || o instanceof Date) {
    return o
  }

  // Array
  if (Array.isArray(o) || o instanceof Int8Array || o instanceof Uint8Array || o instanceof Uint8ClampedArray || o instanceof Int16Array || o instanceof Uint16Array || o instanceof Int32Array || o instanceof Uint32Array || o instanceof Float32Array || o instanceof Float64Array || o instanceof BigInt64Array || o instanceof BigUint64Array) {
    return o.map(e => deepCopy(e))
  }

  // Object
  const finalObject = {}
  for (let k in o) {
    if (o.hasOwnProperty(k)) {
      finalObject[k] = deepCopy(o[k])
    }
  }
  return finalObject
}

function testDeepCopyObject() {
  console.log('Bad { ...a }:')
  console.log('-------------')

  a = { toto: { tata: () => 'Hey Man!' }, titi: 15, e: { f: /\w/ }, g: { h: new Int32Array([1, 2, 3]) }, i: { j: new Date('1970-01-01') } }
  b = { ...a }

  console.log('a', a)
  console.log('b', b)

  console.log('')

  a.toto.tata = 'fkdfjkdfjkdfj'
  a.g.h[2] = 1000
  a.i.j = new Date('2010-12-30')

  console.log('a', a)
  console.log('b', b)

  console.log('')

  console.log('Bad JSON.parse(JSON.stringify(a)):')
  console.log('----------------------------------')

  a = { toto: { tata: () => 'Hey Man!' }, titi: 15, e: { f: /\w/ }, g: { h: new Int32Array([1, 2, 3]) }, i: { j: new Date('1970-01-01') } }
  b = JSON.parse(JSON.stringify(a))

  console.log('a', a)
  console.log('b', b)

  console.log('')

  a.toto.tata = 'fkdfjkdfjkdfj'
  a.g.h[2] = 1000
  a.i.j = new Date('2010-12-30')

  console.log('a', a)
  console.log('b', b)

  console.log('')

  console.log('Good deepCopy:')
  console.log('--------------')

  a = { toto: { tata: () => 'Hey Man!' }, titi: 15, e: { f: /\w/ }, g: { h: new Int32Array([1, 2, 3]) }, i: { j: new Date('1970-01-01') } }
  b = deepCopy(a)

  console.log('a', a)
  console.log('b', b)

  console.log('')

  a.toto.tata = 'fkdfjkdfjkdfj'
  a.g.h[2] = 1000
  a.i.j = new Date('2010-12-30')

  console.log('a', a)
  console.log('b', b)
}

function testDeepCopyArray() {
  console.log('Bad [...a]:')
  console.log('-------------')

  a = [[1, 2, 3], 4, 5, [[6, 7, 8], 9], 0]
  b = [...a]

  console.log('a', a)
  console.log('b', b)

  console.log('')

  a[0][0] = 'ici'
  a[3][0][1] = 'toto'

  console.log('a', a)
  console.log('b', b)

  console.log('')

  console.log('Bad JSON.parse(JSON.stringify(a)):')
  console.log('----------------------------------')

  a = [[1, 2, 3], 4, 5, [[6, 7, 8], 9], 0]
  b = JSON.parse(JSON.stringify(a))

  console.log('a', a)
  console.log('b', b)

  console.log('')

  a[0][0] = 'ici'
  a[3][0][1] = 'toto'

  console.log('a', a)
  console.log('b', b)

  console.log('')

  console.log('Good deepCopy:')
  console.log('--------------')

  a = [[1, 2, 3], 4, 5, [[6, 7, 8], 9], 0]
  b = deepCopy(a)

  console.log('a', a)
  console.log('b', b)

  console.log('')

  a[0][0] = 'ici'
  a[3][0][1] = 'toto'

  console.log('a', a)
  console.log('b', b)
}

testDeepCopyObject()

console.log('')
console.log('')
console.log('')
console.log('')
console.log('')
console.log('')

testDeepCopyArray()