{"record":{"id":"518bb5c1e80134f6","repo":"koala73/worldmonitor","slug":"custom-scorecard-bloc-members-must-be-unique","errorCode":null,"errorMessage":"Custom scorecard bloc members must be unique.","messagePattern":"Custom scorecard bloc members must be unique\\.","errorType":"validation","errorClass":"Error","httpStatus":400,"severity":"error","filePath":"server/worldmonitor/scorecard/v1/_bloc-presets.ts","lineNumber":40,"sourceCode":"    members: ['AL', 'BE', 'BG', 'CA', 'HR', 'CZ', 'DK', 'EE', 'FI', 'FR', 'DE', 'GR', 'HU', 'IS', 'IT', 'LV', 'LT', 'LU', 'ME', 'NL', 'MK', 'NO', 'PL', 'PT', 'RO', 'SK', 'SI', 'ES', 'SE', 'TR', 'GB', 'US'],\n  },\n};\n\nexport function resolveBlocSelection(input: { preset?: string; members?: string[] }): ScorecardBlocSelection {\n  const preset = String(input.preset || '').trim();\n  const members = Array.isArray(input.members) ? input.members : [];\n  if (Boolean(preset) === (members.length > 0)) {\n    throw new Error('Select exactly one scorecard bloc preset or custom member list.');\n  }\n  if (preset) {\n    if (!(preset in SCORECARD_BLOC_PRESETS)) throw new Error(`Unknown scorecard bloc preset: ${preset}`);\n    return SCORECARD_BLOC_PRESETS[preset as ScorecardBlocPreset];\n  }\n  if (members.length < 2 || members.length > 30) throw new Error('Custom scorecard blocs require 2-30 members.');\n  if (members.some((member) => !/^[A-Z]{2}$/.test(member))) {\n    throw new Error('Custom scorecard bloc members must be uppercase ISO-2 codes.');\n  }\n  if (new Set(members).size !== members.length) throw new Error('Custom scorecard bloc members must be unique.');\n  if (members.some((member) => !isInRankableUniverse(member))) {\n    throw new Error('Custom scorecard bloc members must belong to the public rankable country universe.');\n  }\n  const sorted = [...members].sort();\n  return { id: `custom:${sorted.join('-')}`, label: sorted.join(' + '), members: sorted };\n}\n","sourceCodeStart":22,"sourceCodeEnd":47,"githubUrl":"https://github.com/koala73/worldmonitor/blob/9361220cc013571781071f0206e4d80fd14b2f7f/server/worldmonitor/scorecard/v1/_bloc-presets.ts#L22-L47","documentation":"resolveBlocSelection rejects custom member lists containing duplicate country codes, comparing new Set(members).size against members.length. Duplicates would double-weight a country in the scorecard aggregation and inflate the bloc, so they are rejected rather than silently deduplicated. This check runs after the count (2–30) and format (uppercase ISO-2) checks.","triggerScenarios":"Calling getBlocScorecardWithReader with { members: ['US','CA','US','MX'] } — any repeated code, even from merging two lists or a UI that appends to an existing selection.","commonSituations":"1) A multi-select UI appends to the array each time a tag is re-clicked; 2) server-side code merges overlapping blocs (USMCA + custom US list) without deduping; 3) scripted concatenation of two member arrays.","solutions":["Deduplicate before sending: [...new Set(members)].","Fix the picker UI to toggle selection instead of appending duplicates.","After dedup, re-check the 2–30 count — heavy dedup can drop you below the minimum.","Normalize first (trim/uppercase) so 'US' and 'us ' dedupe to one entry."],"exampleFix":"// before\nresolveBlocSelection({ members: ['US', 'CA', 'US'] }); // throws\n// after\nconst members = [...new Set(raw.map((m) => m.trim().toUpperCase()))];\nresolveBlocSelection({ members });","handlingStrategy":"validation","validationCode":"const members = [...new Set(raw.map((m) => String(m).trim().toUpperCase()))];\nif (new Set(members).size !== members.length) throw new Error('duplicate members'); // unreachable after Set, defensive","typeGuard":null,"tryCatchPattern":"try {\n  const bloc = await getBlocScorecard({ members });\n} catch (err) {\n  if (err.message.includes('must be unique')) {\n    return badRequest({ duplicates: findDuplicates(members) });\n  }\n  throw err;\n}","preventionTips":["Always dedupe with a Set before sending member lists","Make the picker toggle selection rather than append","Dedupe when merging overlapping blocs or arrays","Re-check the 2–30 count after deduplication"],"tags":["validation","scorecard","duplicates","bad-request"],"backgroundTag":"invalid-bloc-selection","analyzedSha":"9361220cc013571781071f0206e4d80fd14b2f7f","analyzedAt":"2026-09-01T10:32:37.851Z","contentChangedAt":"2026-09-01T10:32:37.851Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}