perf: slightly more efficient word filter format (#1991)

src/routes/_store/computations/wordFilterComputations.js

@@ -1,4 +1,5 @@
-import { createRegexFromFilter } from '../../_utils/createRegexFromFilter'
+import { createRegexFromFilters } from '../../_utils/createRegexFromFilters'
+import { WORD_FILTER_CONTEXTS } from '../../_static/wordFilters'
 
 export function wordFilterComputations (store) {
   // unexpiredInstanceFilters is calculated based on `now` and `instanceFilters`,
@@ -9,13 +10,17 @@ export function wordFilterComputations (store) {
     (unexpiredInstanceFilters, currentInstance) => unexpiredInstanceFilters[currentInstance] || []
   )
 
-  store.compute('unexpiredInstanceFiltersWithRegexes', ['unexpiredInstanceFilters'], unexpiredInstanceFilters => {
+  store.compute('unexpiredInstanceFilterRegexes', ['unexpiredInstanceFilters'], unexpiredInstanceFilters => {
     return Object.fromEntries(Object.entries(unexpiredInstanceFilters).map(([instanceName, filters]) => {
-      const filtersWithRegexes = filters.map(filter => ({
-        ...filter,
-        regex: createRegexFromFilter(filter)
-      }))
-      return [instanceName, filtersWithRegexes]
+      const contextsToRegex = Object.fromEntries(WORD_FILTER_CONTEXTS.map(context => {
+        const filtersForThisContext = filters.filter(_ => _.context.includes(context))
+        if (!filtersForThisContext.length) {
+          return undefined // don't bother even adding it to the map
+        }
+        const regex = createRegexFromFilters(filtersForThisContext)
+        return [context, regex]
+      }).filter(Boolean))
+      return [instanceName, contextsToRegex]
     }))
   })
 }

src/routes/_store/observers/wordFilterObservers.js

@@ -40,8 +40,8 @@ export function wordFilterObservers () {
     updateUnexpiredInstanceFiltersIfUnchanged(now, instanceFilters)
   })
 
-  store.observe('unexpiredInstanceFiltersWithRegexes', async unexpiredInstanceFiltersWithRegexes => {
-    console.log('unexpiredInstanceFiltersWithRegexes changed, recomputing filterContexts')
+  store.observe('unexpiredInstanceFilterRegexes', async unexpiredInstanceFilterRegexes => {
+    console.log('unexpiredInstanceFilterRegexes changed, recomputing filterContexts')
     mark('update timeline item summary filter contexts')
     // Whenever the filters change, we need to re-compute the filterContexts on the TimelineSummaries.
     // This is a bit of an odd design, but we do it for perf. See timelineItemToSummary.js for details.
@@ -55,7 +55,7 @@ export function wordFilterObservers () {
 
     let somethingChanged = false
 
-    await Promise.all(Object.entries(unexpiredInstanceFiltersWithRegexes).map(async ([instanceName, filtersWithRegexes]) => {
+    await Promise.all(Object.entries(unexpiredInstanceFilterRegexes).map(async ([instanceName, contextsToRegex]) => {
       const timelinesToSummaries = timelineItemSummaries[instanceName] || {}
       const timelinesToSummariesToAdd = timelineItemSummariesToAdd[instanceName] || {}
       const summariesToUpdate = [
@@ -70,7 +70,7 @@ export function wordFilterObservers () {
             ? database.getNotification(instanceName, summary.id)
             : database.getStatus(instanceName, summary.id)
           )
-          const newFilterContexts = computeFilterContextsForStatusOrNotification(item, filtersWithRegexes)
+          const newFilterContexts = computeFilterContextsForStatusOrNotification(item, contextsToRegex)
           if (!isEqual(summary.filterContexts, newFilterContexts)) {
             somethingChanged = true
             summary.filterContexts = newFilterContexts

src/routes/_utils/computeFilterContextsForStatusOrNotification.js

@@ -1,18 +1,16 @@
 import { createSearchIndexFromStatusOrNotification } from './createSearchIndexFromStatusOrNotification'
-import { uniq } from 'lodash-es'
 
-export function computeFilterContextsForStatusOrNotification (statusOrNotification, filtersWithRegexes) {
-  if (!filtersWithRegexes || !filtersWithRegexes.length) {
+export function computeFilterContextsForStatusOrNotification (statusOrNotification, contextsToRegex) {
+  if (!contextsToRegex || !Object.keys(contextsToRegex).length) {
     // avoid computing the search index, just bail out
     return undefined
   }
   // the searchIndex is really just a string of text
   const searchIndex = createSearchIndexFromStatusOrNotification(statusOrNotification)
-  const res = filtersWithRegexes && uniq(filtersWithRegexes
-    .filter(({ regex }) => regex.test(searchIndex))
-    .map(_ => _.context)
-    .flat())
+  const res = Object.entries(contextsToRegex)
+    .filter(([context, regex]) => regex.test(searchIndex))
+    .map(([context]) => context)
 
   // return undefined instead of a new array to reduce memory usage of TimelineSummary
-  return (res && res.length) ? res : undefined
+  return res.length ? res : undefined
 }

src/routes/_utils/createRegexFromFilter.js

@@ -1,20 +0,0 @@
-// copy-pasta'd from mastodon
-// https://github.com/tootsuite/mastodon/blob/2ff01f7/app/javascript/mastodon/selectors/index.js#L40-L63
-const escapeRegExp = string =>
-  string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&') // $& means the whole matched string
-
-export function createRegexFromFilter (filter) {
-  let expr = escapeRegExp(filter.phrase)
-
-  if (filter.whole_word) {
-    if (/^[\w]/.test(expr)) {
-      expr = `\\b${expr}`
-    }
-
-    if (/[\w]$/.test(expr)) {
-      expr = `${expr}\\b`
-    }
-  }
-
-  return new RegExp(expr, 'i')
-}

src/routes/_utils/createRegexFromFilters.js

@@ -0,0 +1,22 @@
+// copy-pasta'd from mastodon
+// https://github.com/tootsuite/mastodon/blob/2ff01f7/app/javascript/mastodon/selectors/index.js#L40-L63
+const escapeRegExp = string =>
+  string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&') // $& means the whole matched string
+
+export const createRegexFromFilters = filters => {
+  return new RegExp(filters.map(filter => {
+    let expr = escapeRegExp(filter.phrase)
+
+    if (filter.whole_word) {
+      if (/^[\w]/.test(expr)) {
+        expr = `\\b${expr}`
+      }
+
+      if (/[\w]$/.test(expr)) {
+        expr = `${expr}\\b`
+      }
+    }
+
+    return expr
+  }).join('|'), 'i')
+}

src/routes/_utils/timelineItemToSummary.js

@@ -13,9 +13,9 @@ class TimelineSummary {
     // 1. Avoid computing html-to-text (expensive) for users who don't have any filters (probably most users)
     // 2. Avoiding keeping the entire html-to-text in memory at all times for all summaries
     // 3. Filters probably change infrequently. When they do, we can just update the summaries
-    const { unexpiredInstanceFiltersWithRegexes } = store.get()
-    const filtersWithRegexes = unexpiredInstanceFiltersWithRegexes[instanceName]
-    this.filterContexts = computeFilterContextsForStatusOrNotification(item, filtersWithRegexes)
+    const { unexpiredInstanceFilterRegexes } = store.get()
+    const contextsToRegex = unexpiredInstanceFilterRegexes[instanceName]
+    this.filterContexts = computeFilterContextsForStatusOrNotification(item, contextsToRegex)
   }
 }