3 ms·

As I understand it, immutability makes management of state on complex objects easier to deal with. Whereas ImmutableJS the library makes immutability performant

As I understand it, immutability makes management of state on complex objects easier to deal with. Whereas ImmutableJS the library makes immutability performant in JS. Someone please correct me if I'm wrong because I cannot seem to locate my source anymore, but I believe what ImmutabilityJS does is not actually deep-copy complex objects, but reuse references to nested objects that have not changed. Such that you get a new object, but not everything in the object is new, which is what keeps things fast.

Cshelton 11y ago
When you use Immutable JS, you are taking a slight performance hit. You are creating a new object every time you change anything and returning it. But the benefit of not having to worry about unexpected changed or sometimes referencing something you didn't mean too is great. The added performance can come from the equality checks. Like, do not do anything if newState === oldState. This has added benefit with something like React where you can use shouldCOmponentUpdate, which we returned false, will not call the render function. It can increase performance drastically on complicated things.
- woah 11y ago
  I think you know this, but just so that nobody gets the wrong idea- the new object created only uses as much memory as the difference between the new object and the old one. Immutablejs keeps track of the diffs and presents an interface to something that acts like a whole new object but consists of the old object + diffs. So if you are replacing some in-place array mutation with Immutablejs code, this will use slightly more memory. However, if you are replacing native .map, .reduce, or .filter code with the equivalent Immutablejs, you will actually use less memory, because the built in methods clone the entire object.

3 ms·

As I understand it, immutability makes management of state on complex objects easier to deal with. Whereas ImmutableJS the library makes immutability performant

by feedjoelpie 11y ago

Cshelton 11y ago
When you use Immutable JS, you are taking a slight performance hit. You are creating a new object every time you change anything and returning it. But the benefit of not having to worry about unexpected changed or sometimes referencing something you didn't mean too is great. The added performance can come from the equality checks. Like, do not do anything if newState === oldState. This has added benefit with something like React where you can use shouldCOmponentUpdate, which we returned false, will not call the render function. It can increase performance drastically on complicated things.
- woah 11y ago
  I think you know this, but just so that nobody gets the wrong idea- the new object created only uses as much memory as the difference between the new object and the old one. Immutablejs keeps track of the diffs and presents an interface to something that acts like a whole new object but consists of the old object + diffs. So if you are replacing some in-place array mutation with Immutablejs code, this will use slightly more memory. However, if you are replacing native .map, .reduce, or .filter code with the equivalent Immutablejs, you will actually use less memory, because the built in methods clone the entire object.