| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | * |
| 7 | * @flow strict |
| 8 | */ |
| 9 | |
| 10 | // ----------------------------------------------------------------------------- |
| 11 | // Land or remove (zero effort) |
| 12 | // |
| 13 | // Flags that can likely be deleted or landed without consequences |
| 14 | // ----------------------------------------------------------------------------- |
| 15 | |
| 16 | // None |
| 17 | |
| 18 | // ----------------------------------------------------------------------------- |
| 19 | // Killswitch |
| 20 | // |
| 21 | // Flags that exist solely to turn off a change in case it causes a regression |
| 22 | // when it rolls out to prod. We should remove these as soon as possible. |
| 23 | // ----------------------------------------------------------------------------- |
| 24 | |
| 25 | // Enables the browser() API exported from react-dom. |
| 26 | export const enableBrowserAPI: boolean = true; |
| 27 | |
| 28 | // ----------------------------------------------------------------------------- |
| 29 | // Land or remove (moderate effort) |
| 30 | // |
| 31 | // Flags that can be probably deleted or landed, but might require extra effort |
| 32 | // like migrating internal callers or performance testing. |
| 33 | // ----------------------------------------------------------------------------- |
| 34 | |
| 35 | // Need to remove didTimeout argument from Scheduler before landing |
| 36 | export const disableSchedulerTimeoutInWorkLoop: boolean = false; |
| 37 | |
| 38 | // ----------------------------------------------------------------------------- |
| 39 | // Slated for removal in the future (significant effort) |
| 40 | // |
| 41 | // These are experiments that didn't work out, and never shipped, but we can't |
| 42 | // delete from the codebase until we migrate internal callers. |
| 43 | // ----------------------------------------------------------------------------- |
| 44 | |
| 45 | // Add a callback property to suspense to notify which promises are currently |
| 46 | // in the update queue. This allows reporting and tracing of what is causing |
| 47 | // the user to see a loading state. |
| 48 | // |
| 49 | // Also allows hydration callbacks to fire when a dehydrated boundary gets |
| 50 | // hydrated or deleted. |
| 51 | // |
| 52 | // This will eventually be replaced by the Transition Tracing proposal. |
| 53 | export const enableSuspenseCallback: boolean = false; |
| 54 | |
| 55 | // Experimental Scope support. |
| 56 | export const enableScopeAPI: boolean = false; |
| 57 | |
| 58 | // Experimental Create Event Handle API. |
| 59 | export const enableCreateEventHandleAPI: boolean = false; |
| 60 | |
| 61 | // Support legacy Primer support on internal FB www |
| 62 | export const enableLegacyFBSupport: boolean = false; |
| 63 | |
| 64 | // ----------------------------------------------------------------------------- |
| 65 | // Ongoing experiments |
| 66 | // |
| 67 | // These are features that we're either actively exploring or are reasonably |
| 68 | // likely to include in an upcoming release. |
| 69 | // ----------------------------------------------------------------------------- |
| 70 | |
| 71 | // Yield to the browser event loop and not just the scheduler event loop before passive effects. |
| 72 | // Fix gated tests that fail with this flag enabled before turning it back on. |
| 73 | export const enableYieldingBeforePassive: boolean = false; |
| 74 | |
| 75 | // Experiment to intentionally yield less to block high framerate animations. |
| 76 | export const enableThrottledScheduling: boolean = false; |
| 77 | |
| 78 | export const enableLegacyCache = __EXPERIMENTAL__; |
| 79 | |
| 80 | export const enableAsyncIterableChildren = __EXPERIMENTAL__; |
| 81 | |
| 82 | // Support thenables with status 'pending_weak' in Flight. A weak-pending |
| 83 | // thenable doesn't keep the stream open; if it resolves before the stream |
| 84 | // closes for other reasons, its value is emitted, otherwise its reference is |
| 85 | // left unfulfilled. |
| 86 | export const enableFlightWeakThenables = __EXPERIMENTAL__; |
| 87 | |
| 88 | export const enableTaint = __EXPERIMENTAL__; |
| 89 | |
| 90 | export const enableViewTransition: boolean = true; |
| 91 | |
| 92 | export const enableViewTransitionParentEnterExit = __EXPERIMENTAL__; |
| 93 | |
| 94 | export const enableViewTransitionForPersistenceMode: boolean = false; |
| 95 | |
| 96 | export const enableGestureTransition = __EXPERIMENTAL__; |
| 97 | |
| 98 | export const enableScrollEndPolyfill = __EXPERIMENTAL__; |
| 99 | |
| 100 | export const enableSuspenseyImages: boolean = false; |
| 101 | |
| 102 | export const enableFizzBlockingRender = __EXPERIMENTAL__; // rel="expect" |
| 103 | |
| 104 | export const enableSrcObject = __EXPERIMENTAL__; |
| 105 | |
| 106 | export const enableHydrationChangeEvent = __EXPERIMENTAL__; |
| 107 | |
| 108 | export const enableDefaultTransitionIndicator = __EXPERIMENTAL__; |
| 109 | |
| 110 | export const enableOptimisticKey = __EXPERIMENTAL__; |
| 111 | |
| 112 | /** |
| 113 | * Switches Fiber creation to a simple object instead of a constructor. |
| 114 | */ |
| 115 | export const enableObjectFiber: boolean = false; |
| 116 | |
| 117 | export const enableTransitionTracing: boolean = false; |
| 118 | |
| 119 | // FB-only usage. The new API has different semantics. |
| 120 | export const enableLegacyHidden: boolean = false; |
| 121 | |
| 122 | // Enables unstable_avoidThisFallback feature in Fiber |
| 123 | export const enableSuspenseAvoidThisFallback: boolean = false; |
| 124 | |
| 125 | export const enableCPUSuspense = __EXPERIMENTAL__; |
| 126 | |
| 127 | // Test this at Meta before enabling. |
| 128 | export const enableNoCloningMemoCache: boolean = false; |
| 129 | |
| 130 | // Test in www before enabling in open source. |
| 131 | // Enables DOM-server to stream its instruction set as data-attributes |
| 132 | // (handled with an MutationObserver) instead of inline-scripts |
| 133 | export const enableFizzExternalRuntime = __EXPERIMENTAL__; |
| 134 | |
| 135 | export const alwaysThrottleRetries: boolean = true; |
| 136 | |
| 137 | // Gate whether useEffectEvent uses the mutation phase (true) or before-mutation |
| 138 | // phase (false) for updating event function references. |
| 139 | export const enableEffectEventMutationPhase: boolean = true; |
| 140 | |
| 141 | export const passChildrenWhenCloningPersistedNodes: boolean = false; |
| 142 | |
| 143 | /** |
| 144 | * Enables an expiration time for retry lanes to avoid starvation. |
| 145 | */ |
| 146 | export const enableRetryLaneExpiration: boolean = false; |
| 147 | export const retryLaneExpirationMs = 5000; |
| 148 | export const syncLaneExpirationMs = 250; |
| 149 | export const transitionLaneExpirationMs = 5000; |
| 150 | |
| 151 | /** |
| 152 | * Enables a new error detection for infinite render loops from updates caused |
| 153 | * by setState or similar outside of the component owning the state. |
| 154 | */ |
| 155 | export const enableInfiniteRenderLoopDetection: boolean = false; |
| 156 | /** |
| 157 | * When `enableInfiniteRenderLoopDetection` is on, forces the detection |
| 158 | * mechanism to throw instead of only warning in cases where it would |
| 159 | * otherwise downgrade to a warning. |
| 160 | */ |
| 161 | export const enableInfiniteRenderLoopDetectionForceThrow: boolean = false; |
| 162 | |
| 163 | export const enableConditionalUseWarning: boolean = __EXPERIMENTAL__; |
| 164 | |
| 165 | export const enableFragmentRefs: boolean = true; |
| 166 | export const enableFragmentRefsScrollIntoView: boolean = true; |
| 167 | export const enableFragmentRefsInstanceHandles: boolean = true; |
| 168 | export const enableFragmentRefsTextNodes: boolean = true; |
| 169 | |
| 170 | export const enableInternalInstanceMap: boolean = false; |
| 171 | |
| 172 | // ----------------------------------------------------------------------------- |
| 173 | // Ready for next major. |
| 174 | // |
| 175 | // Alias __NEXT_MAJOR__ to __EXPERIMENTAL__ for easier skimming. |
| 176 | // ----------------------------------------------------------------------------- |
| 177 | |
| 178 | // TODO: Anything that's set to `true` in this section should either be cleaned |
| 179 | // up (if it's on everywhere, including Meta and RN builds) or moved to a |
| 180 | // different section of this file. |
| 181 | |
| 182 | // const __NEXT_MAJOR__ = __EXPERIMENTAL__; |
| 183 | |
| 184 | /** |
| 185 | * Removes legacy style context defined using static `contextTypes` and consumed with static `childContextTypes`. |
| 186 | */ |
| 187 | export const disableLegacyContext: boolean = true; |
| 188 | /** |
| 189 | * Removes legacy style context just from function components. |
| 190 | */ |
| 191 | export const disableLegacyContextForFunctionComponents: boolean = true; |
| 192 | |
| 193 | // Enable the moveBefore() alternative to insertBefore(). This preserves states of moves. |
| 194 | export const enableMoveBefore: boolean = false; |
| 195 | |
| 196 | // Disabled caching behavior of `react/cache` in client runtimes. |
| 197 | export const disableClientCache: boolean = true; |
| 198 | |
| 199 | // Warn on any usage of ReactTestRenderer |
| 200 | export const enableReactTestRendererWarning: boolean = true; |
| 201 | |
| 202 | // Disables legacy mode |
| 203 | // This allows us to land breaking changes to remove legacy mode APIs in experimental builds |
| 204 | // before removing them in stable in the next Major |
| 205 | export const disableLegacyMode: boolean = true; |
| 206 | |
| 207 | // ----------------------------------------------------------------------------- |
| 208 | // Chopping Block |
| 209 | // |
| 210 | // Planned feature deprecations and breaking changes. Sorted roughly in order of |
| 211 | // when we plan to enable them. |
| 212 | // ----------------------------------------------------------------------------- |
| 213 | |
| 214 | // ----------------------------------------------------------------------------- |
| 215 | // React DOM Chopping Block |
| 216 | // |
| 217 | // Similar to main Chopping Block but only flags related to React DOM. These are |
| 218 | // grouped because we will likely batch all of them into a single major release. |
| 219 | // ----------------------------------------------------------------------------- |
| 220 | |
| 221 | // Disable support for comment nodes as React DOM containers. Already disabled |
| 222 | // in open source, but www codebase still relies on it. Need to remove. |
| 223 | export const disableCommentsAsDOMContainers: boolean = true; |
| 224 | |
| 225 | export const enableTrustedTypesIntegration: boolean = true; |
| 226 | |
| 227 | // Prevent the value and checked attributes from syncing with their related |
| 228 | // DOM properties |
| 229 | export const disableInputAttributeSyncing: boolean = false; |
| 230 | |
| 231 | // Disables children for <textarea> elements |
| 232 | export const disableTextareaChildren: boolean = false; |
| 233 | |
| 234 | // Disables children for <textarea> elements |
| 235 | export const enableParallelTransitions: boolean = true; |
| 236 | |
| 237 | // ----------------------------------------------------------------------------- |
| 238 | // Debugging and DevTools |
| 239 | // ----------------------------------------------------------------------------- |
| 240 | |
| 241 | // Gather advanced timing metrics for Profiler subtrees. |
| 242 | export const enableProfilerTimer = __PROFILE__; |
| 243 | |
| 244 | // Adds performance.measure() marks using Chrome extensions to allow formatted |
| 245 | // Component rendering tracks to show up in the Performance tab. |
| 246 | // This flag will be used for both Server Component and Client Component tracks. |
| 247 | // All calls should also be gated on enableProfilerTimer. |
| 248 | export const enableComponentPerformanceTrack: boolean = true; |
| 249 | |
| 250 | // Enables annotating of React performance track events with `performanceIssue` |
| 251 | // metadata, to more prominently highlight performance issues to users |
| 252 | // (initially, an experimental feature in React Native). |
| 253 | export const enablePerformanceIssueReporting: boolean = false; |
| 254 | |
| 255 | // Adds user timing marks for e.g. state updates, suspense, and work loop stuff, |
| 256 | // for an experimental timeline tool. |
| 257 | export const enableSchedulingProfiler: boolean = |
| 258 | !enableComponentPerformanceTrack && __PROFILE__; |
| 259 | |
| 260 | // Record durations for commit and passive effects phases. |
| 261 | export const enableProfilerCommitHooks = __PROFILE__; |
| 262 | |
| 263 | // Phase param passed to onRender callback differentiates between an "update" and a "cascading-update". |
| 264 | export const enableProfilerNestedUpdatePhase = __PROFILE__; |
| 265 | |
| 266 | export const enableAsyncDebugInfo: boolean = true; |
| 267 | |
| 268 | // Track which Fiber(s) schedule render work. |
| 269 | export const enableUpdaterTracking = __PROFILE__; |
| 270 | |
| 271 | export const ownerStackLimit = 1e4; |
| 272 | |
| 273 | // ----------------------------------------------------------------------------- |
| 274 | // eslint-plugin-react-hooks |
| 275 | // ----------------------------------------------------------------------------- |
| 276 | export const eprh_enableUseKeyedStateCompilerLint: boolean = false; |
| 277 | export const eprh_enableVerboseNoSetStateInEffectCompilerLint: boolean = false; |
| 278 | export const eprh_enableExhaustiveEffectDependenciesCompilerLint: |
| 279 | | 'off' |
| 280 | | 'all' |
| 281 | | 'extra-only' |
| 282 | | 'missing-only' = 'off'; |