javascript - Can a function which returns a new object be considered "pure"? -


given definition:

a pure function function given same input, return same output , produces no side effects.

can consider function amipure pure function? according definition no, want make sure.

function amount(value, currency) {   this.value = value;   this.currency = currency; }  function amipure(value, currency) {   return new amount(value, currency); }  var foo = amipure(5, "sek"); var baz = amipure(5, "sek"); console.log(foo === baz); //false

it depends on definition of "same".

if expect strict object equality, functions returning scalars (e.g. numbers, booleans, ...) ever considered "pure".

in general, though, that's not mean: don't care if the exact same instance of object, if equal according definition, e.g.:

  • if strings equal characters ("hello" , "hello")
  • if simple object equal attribute names , values ({x:0,y:1} , {y:1,x:0})
  • if arrays equal elements in same order ([1,2,3] , [1,2,3])
  • ...

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