'use strict'; class Vertex { constructor(graph, data) { this.graph = graph; this.data = data; this.links = new Map(); } link(...args) { const distinct = new Set(args); const { links } = this; const { keyField } = this.graph; for (const item of distinct) { const value = item.data[keyField]; links.set(value, item); } return this; } } class Cursor { constructor(vertices) { this.vertices = vertices; } linked(...names) { const { vertices } = this; const result = new Set(); for (const vertex of vertices) { let condition = true; for (const name of names) { condition = condition && vertex.links.has(name); } if (condition) result.add(vertex); } return new Cursor(result); } } class Graph { constructor(keyField) { this.keyField = keyField; this.vertices = new Map(); } add(data) { const vertex = new Vertex(this, data); const key = data[this.keyField]; if (this.vertices.get(key) === undefined) { this.vertices.set(key, vertex); } return vertex; } select(query) { const vertices = new Set(); for (const vertex of this.vertices.values()) { let condition = true; const { data } = vertex; if (data) { for (const field in query) { condition = condition && data[field] === query[field]; } if (condition) vertices.add(vertex); } } return new Cursor(vertices); } } // Usage const graph = new Graph('name'); const marcus = graph.add({ name: 'Marcus Aurelius', city: 'Rome', born: 121, dynasty: 'Antonine', }); const lucius = graph.add({ name: 'Lucius Verus', city: 'Rome', born: 130, dynasty: 'Antonine', }); const pius = graph.add({ name: 'Antoninus Pius', city: 'Lanuvium', born: 86, dynasty: 'Antonine', }); const hadrian = graph.add({ name: 'Hadrian', city: 'Santiponce', born: 76, dynasty: 'Nerva–Trajan', }); const trajan = graph.add({ name: 'Trajan', city: 'Sevilla', born: 98, dynasty: 'Nerva–Trajan', }); marcus.link(lucius); lucius.link(trajan, marcus, marcus, marcus); pius.link(marcus, lucius); hadrian.link(trajan); trajan.link(lucius, marcus); console.dir({ graph }, { depth: null }); const res = graph .select({ city: 'Rome', dynasty: 'Antonine' }) .linked('Trajan'); console.log('\nQuery result:\n'); for (const item of res.vertices) { console.dir(item.data); }