File size: 772 Bytes
eb1202c | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | import { onCleanup } from "solid-js"
export function createRefCountMap<T>(
create: (key: string) => T,
remove?: (key: string) => void,
identity: (key: string) => string = (key) => key,
) {
const items = new Map<string, T>()
const refCounts = new Map<string, number>()
return (key: string) => {
const id = identity(key)
onCleanup(() => {
refCounts.set(id, (refCounts.get(id) ?? 0) - 1)
if (refCounts.get(id) === 0) {
remove?.(id)
items.delete(id)
refCounts.delete(id)
}
})
const cached = items.get(id)
if (cached) {
refCounts.set(id, (refCounts.get(id) ?? 0) + 1)
return cached
}
const item = create(key)
items.set(id, item)
refCounts.set(id, 1)
return item
}
}
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