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// Analogous implementation for withReverseReferenceList, for contributions.
// This is all duplicate code and both should be ported to the same underlying
// data form later on.
//
// This implementation uses a global cache (via WeakMap) to attempt to speed
// up subsequent similar accesses.
//
// This has absolutely not been rigorously tested with altering properties of
// data objects in a wiki data array which is reused. If a new wiki data array
// is used, a fresh cache will always be created.
import {input, templateCompositeFrom} from '#composite';
import {exitWithoutDependency} from '#composite/control-flow';
import inputWikiData from './inputWikiData.js';
// Mapping of reference list property to WeakMap.
// Each WeakMap maps a wiki data array to another weak map,
// which in turn maps each referenced thing to an array of
// things referencing it.
const caches = new Map();
export default templateCompositeFrom({
annotation: `withReverseContributionList`,
inputs: {
data: inputWikiData({allowMixedTypes: false}),
list: input({type: 'string'}),
},
outputs: ['#reverseContributionList'],
steps: () => [
exitWithoutDependency({
dependency: input('data'),
value: input.value([]),
mode: input.value('empty'),
}),
{
dependencies: [input.myself(), input('data'), input('list')],
compute: (continuation, {
[input.myself()]: myself,
[input('data')]: data,
[input('list')]: list,
}) => {
if (!caches.has(list)) {
caches.set(list, new WeakMap());
}
const cache = caches.get(list);
if (!cache.has(data)) {
const cacheRecord = new WeakMap();
for (const referencingThing of data) {
const referenceList = referencingThing[list];
// Destructuring {artist} is the only unique part of the
// withReverseContributionList implementation, compared to
// withReverseReferneceList.
for (const {artist: referencedThing} of referenceList) {
if (cacheRecord.has(referencedThing)) {
cacheRecord.get(referencedThing).push(referencingThing);
} else {
cacheRecord.set(referencedThing, [referencingThing]);
}
}
}
cache.set(data, cacheRecord);
}
return continuation({
['#reverseContributionList']:
cache.get(data).get(myself) ?? [],
});
},
},
],
});
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