Function flattenJSON

frontend/src/hooks/stream/useStreamingJSONParser.ts:115–167

(json: any[])

   * Flatten JSON for tabular display
   */
  const flattenJSON = (json: any[]): [string[][], JsonSchema] => {
    if (!json || json.length === 0) return [[], { properties: {}, isNested: false }];
    
    // Collect all property names
    const properties = new Set<string>();
    for (const item of json) {
      if (item && typeof item === 'object') {
        Object.keys(item).forEach(key => properties.add(key));
      }
    }
    
    // Create header row
    const headers = Array.from(properties);
    const rows: string[][] = [headers];
    
    // Detect property types
    const propertyTypes = detectPropertyTypes(json);
    
    // Check if JSON is nested
    const isNested = isNestedJSON(json);
    
    // Build schema information
    const schema: JsonSchema = {
      properties: propertyTypes,
      isNested
    };
    
    // Flatten each item into a row
    for (const item of json) {
      const row: string[] = [];
      
      for (const prop of headers) {
        if (item && typeof item === 'object' && prop in item) {
          const value = item[prop];
          
          if (value === null || value === undefined) {
            row.push('');
          } else if (typeof value === 'object') {
            // For objects and arrays, convert to string representation
            row.push(JSON.stringify(value));
          } else {
            row.push(String(value));
          }
        } else {
          row.push('');
        }
      }
      
      rows.push(row);
    }
    
    return [rows, schema];
  };

  /**
   * Stream and parse a JSON file