| 1 | import {identity, mutate} from 'shared-runtime'; |
| 2 | |
| 3 | /** |
| 4 | * Currently, InferReactiveScopeVariables do not ensure that maybe-aliased |
| 5 | * values get assigned the same reactive scope. This is safe only when an |
| 6 | * already-constructed value is captured, e.g. |
| 7 | * ```js |
| 8 | * const x = makeObj(); ⌝ mutable range of x |
| 9 | * mutate(x); ⌟ |
| 10 | * <-- after this point, we can produce a canonical version |
| 11 | * of x for all following aliases |
| 12 | * const y = []; |
| 13 | * y.push(x); <-- y captures x |
| 14 | * ``` |
| 15 | * |
| 16 | * However, if a value is captured/aliased during its mutable range and the |
| 17 | * capturing container is separately memoized, it becomes difficult to guarantee |
| 18 | * that all aliases refer to the same value. |
| 19 | * |
| 20 | */ |
| 21 | function useFoo({a, b}) { |
| 22 | const x = {a}; |
| 23 | const y = {}; |
| 24 | mutate(x); |
| 25 | const z = [identity(y), b]; |
| 26 | mutate(y); |
| 27 | |
| 28 | if (z[0] !== y) { |
| 29 | throw new Error('oh no!'); |
| 30 | } |
| 31 | return z; |
| 32 | } |
| 33 | |
| 34 | export const FIXTURE_ENTRYPOINT = { |
| 35 | fn: useFoo, |
| 36 | params: [{a: 2, b: 3}], |
| 37 | sequentialRenders: [ |
| 38 | {a: 2, b: 3}, |
| 39 | {a: 4, b: 3}, |
| 40 | ], |
| 41 | }; |