Msirkovsky

const friends1 = #["G. Lestrade"]
friends2 = friends1.pushed("Dr. Watson")
// tup1 == #["G. Lestrade"]
// tup2 == #["G. Lestrade", "Dr. Watson"]

const tup3 = #["G. Lestrade", "Dr. Watson"]
const tup4 = tup2.sorted 
// tup3 == #["G. Lestrade", "Dr. Watson"]
// tup4 == #["Dr. Watson", "G. Lestrade"]

Msirkovsky

const user = #{ name: "S. Holmes",  age: 27 }

// with immutable types, you are restricted to changing value directly:
user.age = 28 // throws error 

// but, this works:
const userOneYearOlder = #{ ...user, age: 28} // =>  #{ name: "S. Holmes",  age: 28 }
// It also means:
user == userOneYearOlder // => false

Msirkovsky

const primitive = "string is an immutable primitive"
const primitive2 = primitive + " - change it"
primitive  !== primitive2 

const obj1 = { value: 1}
const obj2 = obj1
obj2.value = 2 // change
obj1 === obj2 // => true

// Restricted use:

Msirkovsky

const friends1 = #["G. Lestrade", "John Hamish Watson"]
const friends2 = #["G. Lestrade", "John Hamish Watson"]
friends1 == friends2 // => true

// But

const friends1 = #["G. Lestrade", "John Hamish Watson"]
const friends2 = #["John Hamish Watson", "G. Lestrade"]
friends1 == friends2 // => false

Msirkovsky

const user1 = { name: "S. Holmes",  age: 27 }
const user2 = { age: 27, name: "S. Holmes"}
user1  == user2 // => true

Msirkovsky

// value equality
const user = #{ name: "Dr. Watson"}
const user2 = #{ name: "Dr. Watson"}
const user2 == user // => true

Msirkovsky

//Identity equality 
const user = { name: "Dr. Watson"}
const userRef = user
userRef == user // => true

const user = { name: "Dr. Watson"}
const user2 = { name: "Dr. Watson"}
const user2 == user // => false

Msirkovsky

// Immutable.JS
const record1 = Record({ a: 1, b: 2 }) 
const record2 = record1.set('b', 50)
const b = record2.get('b')

const recordA = Record({ a: 1, b: 2 }) 
const recordB = Record({ a: 1, b: 2 }) 
recordA.equals(recordB) //true
recordA == (recordB) //false

Msirkovsky

// nested primitive and immutable type
const record = #{ name: "Primitive value", number: 33, nestedRecord : #{ number: 50} }

// nested primitive and immutable type
const tuple = #[ "Primitive value",  33,  #{ number: 50}, #[1, true, null] }

// record with a nested object instead of record throws an error as it's not a primitive type anymore
const record = #{ name: "Primitive value", number: 33, nestedObject: { number: 50} } 

Msirkovsky

// the compound value:
// consists of two primitive type
const object = { name: "Primitive value", number: 33 }

// consists of two primitive types & one function
const object = { name: "Primitive value", number: 33, fn: () => {} }