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Aggregation

Aggregate node and edge properties using SUM, AVG, MIN, MAX operations.

Overview​

Grafio provides property aggregation functions that compute statistics across nodes or edges sharing a property key.

aggregateNodeProperty()​

async aggregateNodeProperty(
  key: string,
  options?: GraphQueryOptions
): Promise<AggregateResult>

Computes aggregate statistics for a node property.

AggregateResult​

interface AggregateResult {
  count: number;   // Count of non-null values (always present)
  sum?: number;    // Sum of values (SUM operation)
  avg?: number;    // Average of values (AVG operation)
  min?: number;    // Minimum value (MIN operation)
  max?: number;    // Maximum value (MAX operation)
}

Basic Example​

import { InMemoryGraphFactory } from 'grafio';

const factory = new InMemoryGraphFactory();
const graph = factory.forGraph();

// Add products with prices
await graph.addNode('Product', { name: 'Laptop', price: 999 });
await graph.addNode('Product', { name: 'Phone', price: 699 });
await graph.addNode('Product', { name: 'Tablet', price: 449 });

// Aggregate prices
const result = await graph.aggregateNodeProperty('price');
console.log(result);
// { count: 3, sum: 2147, avg: 715.67, min: 449, max: 999 }

With Type Filter​

// Only aggregate prices for Product nodes
const result = await graph.aggregateNodeProperty('price', {
  filter: { types: ['Product'] }
});

Using Distinct​

// Count unique prices (deduplicate values)
const result = await graph.aggregateNodeProperty('price', {
  distinct: true
});

aggregateEdgeProperty()​

async aggregateEdgeProperty(
  key: string,
  options?: GraphQueryOptions
): Promise<AggregateResult>

Computes aggregate statistics for an edge property.

Example: Order Weights​

// Add shipping relationships with weights
await graph.addEdge('warehouse1', 'store1', 'SHIPS', { weight: 150 });
await graph.addEdge('warehouse1', 'store2', 'SHIPS', { weight: 200 });
await graph.addEdge('warehouse1', 'store3', 'SHIPS', { weight: 175 });

// Aggregate shipment weights
const result = await graph.aggregateEdgeProperty('weight', {
  filter: { types: ['SHIPS'] }
});
console.log(result);
// { count: 3, sum: 525, avg: 175, min: 150, max: 200 }

Common Use Cases​

Average Rating​

// Products with customer ratings
await graph.addNode('Product', { name: 'Widget', rating: 4.5 });
await graph.addNode('Product', { name: 'Gadget', rating: 4.8 });
await graph.addNode('Product', { name: 'Tool', rating: 4.2 });

const result = await graph.aggregateNodeProperty('rating');
console.log(`Average rating: ${result.avg?.toFixed(1)}`); // "Average rating: 4.5"

Minimum/Maximum Values​

// Find temperature ranges in sensor data
const tempResult = await graph.aggregateNodeProperty('temperature');
console.log(`Range: ${tempResult.min}°C - ${tempResult.max}°C`);

Count by Type​

// Count users by status
const userCount = await graph.aggregateNodeProperty('status', {
  filter: { types: ['User'] }
});
console.log(`Total users: ${userCount.count}`);

With Cypher Queries​

Aggregation works seamlessly with Cypher:

MATCH (p:Product)
RETURN count(p) AS count, avg(p.price) AS avgPrice, min(p.price) AS minPrice, max(p.price) AS maxPrice

Next Steps​