Components using selectors rerender when original atom changes? about recoil

[davidmccabe]

Atoms are the unit of subscription and their values are treated as opaque. Recoil doesn't know which parts of an atom's value a particular selector is actually using.

In this example you would decompose the X and Y coordinates into separate atoms.

[ahmedlhanafy]

@davidmccabe But why would one use a selector then? Is it purely for logically grouping atoms?

[drarmstr]

Selectors can be thought of as functions to transform and compute some derived state based on other atoms or selectors. They only trigger re-renders in components which use them when one of their dependencies is updated. Selectors can also be used for integrating asynchronous work or requests with Recoil.

If a component is using selector S and selector S depends on atoms A and B, then the component will re-render if either A or B are updated. This is transitive, so if a components uses selector T, which depends on selector S, then it will also re-render when A or B are updated.

[ahmedlhanafy]

Fair enough. Thanks folks!