{"record":{"id":"496ef8e8c387c078","repo":"facebook/react","slug":"334-496ef8","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/accumulateInto.js","lineNumber":30,"sourceCode":"/**\n * Accumulates items that must not be null or undefined into the first one. This\n * is used to conserve memory by avoiding array allocations, and thus sacrifices\n * API cleanness. Since `current` can be null before being passed in and not\n * null after this function, make sure to assign it back to `current`:\n *\n * `a = accumulateInto(a, b);`\n *\n * This API should be sparingly used. Try `accumulate` for something cleaner.\n *\n * @return {*|array<*>} An accumulation of items.\n */\n\nfunction accumulateInto<T>(\n  current: ?(Array<T> | 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    if (isArray(next)) {\n      // $FlowFixMe[incompatible-use] `isArray` does not ensure array is mutable\n      // $FlowFixMe[method-unbinding]\n      current.push.apply(current, next);\n      return current;\n    }\n    // $FlowFixMe[incompatible-use] `isArray` does not ensure array is mutable\n    current.push(next);\n    return current;","sourceCodeStart":12,"sourceCodeEnd":48,"githubUrl":"https://github.com/facebook/react/blob/eafeac097ba51e1eab809c07102126bd5f8e5425/packages/react-native-renderer/src/legacy-events/accumulateInto.js#L12-L48","documentation":"Error \"Accumulated items must not be null or undefined.\" thrown in facebook/react.","triggerScenarios":"Thrown at packages/react-native-renderer/src/legacy-events/accumulateInto.js:30 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":"2026-08-22T04:17:13.399Z"}