diff --git a/src/routes/_actions/addStatusOrNotification.js b/src/routes/_actions/addStatusOrNotification.js
index fb81b318..25248374 100644
--- a/src/routes/_actions/addStatusOrNotification.js
+++ b/src/routes/_actions/addStatusOrNotification.js
@@ -3,7 +3,7 @@ import { store } from '../_store/store'
 import uniqBy from 'lodash-es/uniqBy'
 import isEqual from 'lodash-es/isEqual'
 import { database } from '../_database/database'
-import { concat, indexWhere } from '../_utils/arrays'
+import { concat } from '../_utils/arrays'
 import { scheduleIdleTask } from '../_utils/scheduleIdleTask'
 import { timelineItemToSummary } from '../_utils/timelineItemToSummary'
 
@@ -47,9 +47,9 @@ function isValidStatusForThread (thread, timelineName, itemSummariesToAdd) {
   let itemSummariesToAddIdSet = new Set(itemSummariesToAdd.map(_ => _.id))
   let threadIdSet = new Set(thread.map(_ => _.id))
   let focusedStatusId = timelineName.split('/')[1] // e.g. "status/123456"
-  let focusedStatusIdx = indexWhere(thread, _ => _.id === focusedStatusId)
+  let focusedStatusIdx = thread.findIndex(_ => _.id === focusedStatusId)
   return status => {
-    let repliedToStatusIdx = indexWhere(thread, _ => _.id === status.in_reply_to_id)
+    let repliedToStatusIdx = thread.findIndex(_ => _.id === status.in_reply_to_id)
     return (
       // A reply to an ancestor status is not valid for this thread, but for the focused status
       // itself or any of its descendents, it is valid.
diff --git a/src/routes/_utils/arrays.js b/src/routes/_utils/arrays.js
index 4a4cd6cf..665c8a02 100644
--- a/src/routes/_utils/arrays.js
+++ b/src/routes/_utils/arrays.js
@@ -44,12 +44,3 @@ export function concat () {
   }
   return res
 }
-
-export function indexWhere (arr, cb) {
-  for (let i = 0; i < arr.length; i++) {
-    if (cb(arr[i], i)) {
-      return i
-    }
-  }
-  return -1
-}
diff --git a/tests/spec/008-status-media.js b/tests/spec/008-status-media.js
index 9d5fc7d2..e643a204 100644
--- a/tests/spec/008-status-media.js
+++ b/tests/spec/008-status-media.js
@@ -2,7 +2,6 @@ import { closeDialogButton, getNthStatus, getNthStatusSelector, modalDialogConte
 import { loginAsFoobar } from '../roles'
 import { Selector as $ } from 'testcafe'
 import { homeTimeline } from '../fixtures'
-import { indexWhere } from '../../src/routes/_utils/arrays'
 
 fixture`008-status-media.js`
   .page`http://localhost:4002`
@@ -10,8 +9,8 @@ fixture`008-status-media.js`
 test('shows sensitive images and videos', async t => {
   await loginAsFoobar(t)
 
-  let kittenIdx = indexWhere(homeTimeline, _ => _.spoiler === 'kitten CW')
-  let videoIdx = indexWhere(homeTimeline, _ => _.content === 'secret video')
+  let kittenIdx = homeTimeline.findIndex(_ => _.spoiler === 'kitten CW')
+  let videoIdx = homeTimeline.findIndex(_ => _.content === 'secret video')
 
   await scrollToStatus(t, 1 + kittenIdx)
   await t.expect($(`${getNthStatusSelector(1 + kittenIdx)} .status-media img`).exists).notOk()
@@ -27,8 +26,8 @@ test('shows sensitive images and videos', async t => {
 test('click and close image and video modals', async t => {
   await loginAsFoobar(t)
 
-  let videoIdx = indexWhere(homeTimeline, _ => _.content === "here's a video")
-  let kittenIdx = indexWhere(homeTimeline, _ => _.content === "here's an animated kitten gif")
+  let videoIdx = homeTimeline.findIndex(_ => _.content === "here's a video")
+  let kittenIdx = homeTimeline.findIndex(_ => _.content === "here's an animated kitten gif")
 
   await scrollToStatus(t, 1 + videoIdx)
   await t.expect(modalDialogContents.exists).notOk()
diff --git a/tests/spec/010-focus.js b/tests/spec/010-focus.js
index 981cc3f8..21442f63 100644
--- a/tests/spec/010-focus.js
+++ b/tests/spec/010-focus.js
@@ -5,7 +5,7 @@ import {
 } from '../utils'
 import { loginAsFoobar } from '../roles'
 import { Selector as $ } from 'testcafe'
-import { indexWhere } from '../../src/routes/_utils/arrays'
+
 import { homeTimeline } from '../fixtures'
 
 fixture`010-focus.js`
@@ -14,7 +14,7 @@ fixture`010-focus.js`
 test('modal preserves focus', async t => {
   await loginAsFoobar(t)
 
-  let idx = indexWhere(homeTimeline, _ => _.content === "here's a video")
+  let idx = homeTimeline.findIndex(_ => _.content === "here's a video")
 
   await scrollToStatus(t, 1 + idx)
   // explicitly hover-focus-click
diff --git a/tests/spec/017-compose-reply.js b/tests/spec/017-compose-reply.js
index 0d01a4e6..40ca1d0c 100644
--- a/tests/spec/017-compose-reply.js
+++ b/tests/spec/017-compose-reply.js
@@ -7,7 +7,6 @@ import {
 } from '../utils'
 import { loginAsFoobar } from '../roles'
 import { homeTimeline } from '../fixtures'
-import { indexWhere } from '../../src/routes/_utils/arrays'
 
 fixture`017-compose-reply.js`
   .page`http://localhost:4002`
@@ -63,7 +62,7 @@ test('replies have same privacy as replied-to status by default', async t => {
 
 test('replies have same CW as replied-to status', async t => {
   await loginAsFoobar(t)
-  let kittenIdx = indexWhere(homeTimeline, _ => _.spoiler === 'kitten CW')
+  let kittenIdx = homeTimeline.findIndex(_ => _.spoiler === 'kitten CW')
   await scrollToStatus(t, 1 + kittenIdx)
   await t.click(getNthReplyButton(1 + kittenIdx))
     .expect(getNthReplyContentWarningInput(1 + kittenIdx).value).eql('kitten CW')
@@ -75,7 +74,7 @@ test('replies have same CW as replied-to status', async t => {
 
 test('replies save deletions of CW', async t => {
   await loginAsFoobar(t)
-  let kittenIdx = indexWhere(homeTimeline, _ => _.spoiler === 'kitten CW')
+  let kittenIdx = homeTimeline.findIndex(_ => _.spoiler === 'kitten CW')
   await scrollToStatus(t, 1 + kittenIdx)
   await t.click(getNthReplyButton(1 + kittenIdx))
     .expect(getNthReplyContentWarningInput(1 + kittenIdx).value).eql('kitten CW')
@@ -89,7 +88,7 @@ test('replies save deletions of CW', async t => {
 
 test('replies save changes to CW', async t => {
   await loginAsFoobar(t)
-  let kittenIdx = indexWhere(homeTimeline, _ => _.spoiler === 'kitten CW')
+  let kittenIdx = homeTimeline.findIndex(_ => _.spoiler === 'kitten CW')
   await scrollToStatus(t, 1 + kittenIdx)
   await t.click(getNthReplyButton(1 + kittenIdx))
     .expect(getNthReplyContentWarningInput(1 + kittenIdx).value).eql('kitten CW')
diff --git a/tests/spec/022-status-aria-label.js b/tests/spec/022-status-aria-label.js
index b5dd808d..7978b656 100644
--- a/tests/spec/022-status-aria-label.js
+++ b/tests/spec/022-status-aria-label.js
@@ -8,7 +8,7 @@ import {
   settingsNavButton
 } from '../utils'
 import { Selector as $ } from 'testcafe'
-import { indexWhere } from '../../src/routes/_utils/arrays'
+
 import { homeTimeline } from '../fixtures'
 
 fixture`022-status-aria-label.js`
@@ -29,7 +29,7 @@ test('basic aria-labels for statuses', async t => {
 
 test('aria-labels for CWed statuses', async t => {
   await loginAsFoobar(t)
-  let kittenIdx = indexWhere(homeTimeline, _ => _.spoiler === 'kitten CW')
+  let kittenIdx = homeTimeline.findIndex(_ => _.spoiler === 'kitten CW')
   await scrollToStatus(t, 1 + kittenIdx)
   await t
     .hover(getNthStatus(1 + kittenIdx))
diff --git a/tests/spec/023-mark-media-as-sensitive.js b/tests/spec/023-mark-media-as-sensitive.js
index 4d4763b9..50040d1e 100644
--- a/tests/spec/023-mark-media-as-sensitive.js
+++ b/tests/spec/023-mark-media-as-sensitive.js
@@ -4,7 +4,7 @@ import {
   getNthStatus, getNthStatusMedia, getNthStatusSensitiveMediaButton, homeNavButton, markMediaSensitiveInput,
   scrollToStatus, settingsNavButton, neverMarkMediaSensitiveInput
 } from '../utils'
-import { indexWhere } from '../../src/routes/_utils/arrays'
+
 import { homeTimeline } from '../fixtures'
 
 fixture`023-mark-media-as-sensitive.js`
@@ -23,11 +23,11 @@ async function checkSensitivityForStatus (t, idx, sensitive) {
 }
 
 async function checkSensitivity (t, shouldBeSensitive) {
-  let sensitiveKittenIdx = indexWhere(homeTimeline, _ => _.spoiler === 'kitten CW')
-  let sensitiveVideoIdx = indexWhere(homeTimeline, _ => _.content === 'secret video')
-  let videoIdx = indexWhere(homeTimeline, _ => _.content === "here's a video")
-  let sensitiveAnimatedKittenIdx = indexWhere(homeTimeline, _ => _.content === "here's a secret animated kitten gif")
-  let animatedKittenIdx = indexWhere(homeTimeline, _ => _.content === "here's an animated kitten gif")
+  let sensitiveKittenIdx = homeTimeline.findIndex(_ => _.spoiler === 'kitten CW')
+  let sensitiveVideoIdx = homeTimeline.findIndex(_ => _.content === 'secret video')
+  let videoIdx = homeTimeline.findIndex(_ => _.content === "here's a video")
+  let sensitiveAnimatedKittenIdx = homeTimeline.findIndex(_ => _.content === "here's a secret animated kitten gif")
+  let animatedKittenIdx = homeTimeline.findIndex(_ => _.content === "here's an animated kitten gif")
 
   await t.hover(getNthStatus(1))
 
diff --git a/tests/spec/025-shortcuts-status.js b/tests/spec/025-shortcuts-status.js
index 7349ba5b..c1413686 100644
--- a/tests/spec/025-shortcuts-status.js
+++ b/tests/spec/025-shortcuts-status.js
@@ -13,7 +13,7 @@ import {
 } from '../utils'
 import { homeTimeline } from '../fixtures'
 import { loginAsFoobar } from '../roles'
-import { indexWhere } from '../../src/routes/_utils/arrays'
+
 import { Selector as $ } from 'testcafe'
 
 fixture`025-shortcuts-status.js`
@@ -80,7 +80,7 @@ test('Shortcut o opens active status, backspace goes back', async t => {
 })
 
 test('Shortcut x shows/hides spoilers', async t => {
-  let idx = indexWhere(homeTimeline, _ => _.spoiler === 'kitten CW')
+  let idx = homeTimeline.findIndex(_ => _.spoiler === 'kitten CW')
   await loginAsFoobar(t)
   await t
     .expect(getUrl()).eql('http://localhost:4002/')
@@ -96,7 +96,7 @@ test('Shortcut x shows/hides spoilers', async t => {
 })
 
 test('Shortcut y shows/hides sensitive image', async t => {
-  let idx = indexWhere(homeTimeline, _ => _.content === "here's a secret kitten")
+  let idx = homeTimeline.findIndex(_ => _.content === "here's a secret kitten")
   await loginAsFoobar(t)
   await t
     .expect(getUrl()).eql('http://localhost:4002/')
@@ -112,7 +112,7 @@ test('Shortcut y shows/hides sensitive image', async t => {
 })
 
 test('Shortcut f toggles favorite status', async t => {
-  let idx = indexWhere(homeTimeline, _ => _.content === 'this is unlisted')
+  let idx = homeTimeline.findIndex(_ => _.content === 'this is unlisted')
   await loginAsFoobar(t)
   await t
     .expect(getUrl()).eql('http://localhost:4002/')
@@ -127,7 +127,7 @@ test('Shortcut f toggles favorite status', async t => {
 })
 
 test('Shortcut p toggles profile', async t => {
-  let idx = indexWhere(homeTimeline, _ => _.content === 'pinned toot 1')
+  let idx = homeTimeline.findIndex(_ => _.content === 'pinned toot 1')
   await loginAsFoobar(t)
   await t
     .expect(getUrl()).eql('http://localhost:4002/')
@@ -139,7 +139,7 @@ test('Shortcut p toggles profile', async t => {
 })
 
 test('Shortcut m toggles mention', async t => {
-  let idx = indexWhere(homeTimeline, _ => _.content === 'pinned toot 1')
+  let idx = homeTimeline.findIndex(_ => _.content === 'pinned toot 1')
   await loginAsFoobar(t)
   await t
     .expect(getUrl()).eql('http://localhost:4002/')
diff --git a/tests/spec/029-back-button-modal.js b/tests/spec/029-back-button-modal.js
index c70ed124..322f5c43 100644
--- a/tests/spec/029-back-button-modal.js
+++ b/tests/spec/029-back-button-modal.js
@@ -20,7 +20,7 @@ import {
   visibleModalDialog
 } from '../utils'
 import { loginAsFoobar } from '../roles'
-import { indexWhere } from '../../src/routes/_utils/arrays'
+
 import { homeTimeline } from '../fixtures'
 
 fixture`029-back-button-modal.js`
@@ -28,7 +28,7 @@ fixture`029-back-button-modal.js`
 
 test('Back button dismisses the modal', async t => {
   await loginAsFoobar(t)
-  let idx = indexWhere(homeTimeline, _ => (_.content || '').includes('2 kitten photos'))
+  let idx = homeTimeline.findIndex(_ => (_.content || '').includes('2 kitten photos'))
   await scrollToStatus(t, idx + 1)
   await t
     .expect(getUrl()).eql('http://localhost:4002/')
diff --git a/tests/spec/030-shortcuts-modal.js b/tests/spec/030-shortcuts-modal.js
index a39e1d82..82e82822 100644
--- a/tests/spec/030-shortcuts-modal.js
+++ b/tests/spec/030-shortcuts-modal.js
@@ -4,7 +4,7 @@ import {
   modalDialog, scrollToStatus, sleep
 } from '../utils'
 import { loginAsFoobar } from '../roles'
-import { indexWhere } from '../../src/routes/_utils/arrays'
+
 import { homeTimeline } from '../fixtures'
 
 fixture`030-shortcuts-modal.js`
@@ -23,7 +23,7 @@ test('Backspace dismisses modal', async t => {
 
 test('Backspace dismisses media modal', async t => {
   await loginAsFoobar(t)
-  let idx = indexWhere(homeTimeline, _ => (_.content || '').includes('2 kitten photos'))
+  let idx = homeTimeline.findIndex(_ => (_.content || '').includes('2 kitten photos'))
   await scrollToStatus(t, idx + 1)
   await t
     .click(getNthStatusMediaButton(idx + 1))
@@ -36,7 +36,7 @@ test('Backspace dismisses media modal', async t => {
 
 test('Left/right changes active media in modal', async t => {
   await loginAsFoobar(t)
-  let idx = indexWhere(homeTimeline, _ => (_.content || '').includes('2 kitten photos'))
+  let idx = homeTimeline.findIndex(_ => (_.content || '').includes('2 kitten photos'))
   await scrollToStatus(t, idx + 1)
   await t
     .click(getNthStatusMediaButton(idx + 1))
diff --git a/tests/spec/100-favorite-unfavorite.js b/tests/spec/100-favorite-unfavorite.js
index 8da9f216..8546295c 100644
--- a/tests/spec/100-favorite-unfavorite.js
+++ b/tests/spec/100-favorite-unfavorite.js
@@ -4,7 +4,7 @@ import {
   scrollToBottom, scrollToTop, sleep
 } from '../utils'
 import { loginAsFoobar } from '../roles'
-import { indexWhere } from '../../src/routes/_utils/arrays'
+
 import { homeTimeline } from '../fixtures'
 
 fixture`100-favorite-unfavorite.js`
@@ -63,7 +63,7 @@ test('unfavorites a status', async t => {
 
 test('Keeps the correct favorites count', async t => {
   await loginAsFoobar(t)
-  let idx = indexWhere(homeTimeline, _ => _.content === 'this is unlisted')
+  let idx = homeTimeline.findIndex(_ => _.content === 'this is unlisted')
   await t
     .hover(getNthStatus(1 + idx))
     .click(getNthFavoriteButton(1 + idx))