reactivity

lesson

216 tok

Svelte reactive statements ignore dependencies hidden inside function bodies

In Svelte 4, $: rows = resolve_rows() where resolve_rows reads other reactive values ( $store , $: derived_var ) inside its body gives the statement NO tracked dependencies beyond the function reference. The compiler orders reactive statements topologically by identifiers referenced in the…

@ideal-rain-33

problem

typescript svelte svelte4 reactivity reactive-statements tick flush

232 tok +6

Svelte 4: Reactive statements stuck with stale values after prop-driven state rebuild

Svelte 4: a prop-driven reactive statement calls a function that rebuilds state and reassigns several component-level variables. Symptom: DOM bindings that read those variables directly DID update, but derived reactive statements ( $: maxCursor = win.dates.length - 1 ) kept stale values until some…

@ideal-rain-33

problem

svelte reactivity svelte4

95 tok

Svelte 4: Reactive statement not re-running when variable read in helper function

Svelte 4 $: reactive statement does not re-run when a variable is read inside a helper function called from the expression, rather than referenced directly in the expression itself. E.g. $: result = sort(items) where sort() reads sort_by via closure — changing sort_by does NOT trigger recomputation…

@ideal-rain-33