{"record":{"id":"7aa4afa7f3c0d7fb","repo":"facebook/react","slug":"334","errorCode":"334","errorMessage":"Accumulated items must not be null or undefined.","messagePattern":"Accumulated items must not be null or undefined\\.","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"packages/react-native-renderer/src/legacy-events/accumulate.js","lineNumber":24,"sourceCode":" *\n * @flow\n */\n\nimport isArray from 'shared/isArray';\n\n/**\n * Accumulates items that must not be null or undefined.\n *\n * This is used to conserve memory by avoiding array allocations.\n *\n * @return {*|array<*>} An accumulation of items.\n */\nfunction accumulate<T>(\n  current: ?(T | Array<T>),\n  next: T | Array<T>,\n): T | Array<T> {\n  if (next == null) {\n    throw new Error('Accumulated items must not be null or undefined.');\n  }\n\n  if (current == null) {\n    return next;\n  }\n\n  // Both are not empty. Warning: Never call x.concat(y) when you are not\n  // certain that x is an Array (x could be a string with concat method).\n  if (isArray(current)) {\n    // $FlowFixMe[incompatible-use] `isArray` does not ensure array is mutable\n    return current.concat(next);\n  }\n\n  if (isArray(next)) {\n    /* $FlowFixMe[incompatible-return] unsound if `next` is `T` and `T` an array,\n     * `isArray` might refine to the array element type of `T` */\n    return [current].concat(next);\n  }","sourceCodeStart":6,"sourceCodeEnd":42,"githubUrl":"https://github.com/facebook/react/blob/eafeac097ba51e1eab809c07102126bd5f8e5425/packages/react-native-renderer/src/legacy-events/accumulate.js#L6-L42","documentation":"Error \"Accumulated items must not be null or undefined.\" thrown in facebook/react.","triggerScenarios":"Thrown at packages/react-native-renderer/src/legacy-events/accumulate.js:24 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"eafeac097ba51e1eab809c07102126bd5f8e5425","analyzedAt":"2026-08-21T22:01:08.818Z","schemaVersion":2},"datasetVersion":"2026-08-21T23:17:16.201Z"}