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| 1 | +'use strict'; |
| 2 | + |
| 3 | +class Vertex { |
| 4 | + constructor(graph, data) { |
| 5 | + this.graph = graph; |
| 6 | + this.data = data; |
| 7 | + this.links = new Map(); |
| 8 | + } |
| 9 | + link(...args) { |
| 10 | + const distinct = new Set(args); |
| 11 | + const links = this.links; |
| 12 | + const keyField = this.graph.keyField; |
| 13 | + let item, key; |
| 14 | + for (item of distinct) { |
| 15 | + key = item.data[keyField]; |
| 16 | + links.set(key, null); |
| 17 | + } |
| 18 | + return this; |
| 19 | + } |
| 20 | +} |
| 21 | + |
| 22 | +class Cursor { |
| 23 | + constructor(vertices) { |
| 24 | + this.vertices = vertices; |
| 25 | + } |
| 26 | + linked(...names) { |
| 27 | + const vertices = this.vertices; |
| 28 | + const result = new Set(); |
| 29 | + let vertex, condition, name; |
| 30 | + for (vertex of vertices) { |
| 31 | + condition = true; |
| 32 | + for (name of names) { |
| 33 | + condition = condition && vertex.links.has(name); |
| 34 | + } |
| 35 | + if (condition) result.add(vertex); |
| 36 | + } |
| 37 | + return new Cursor(result); |
| 38 | + } |
| 39 | +} |
| 40 | + |
| 41 | +class Graph { |
| 42 | + constructor(keyField) { |
| 43 | + this.keyField = keyField; |
| 44 | + this.vertices = new Map(); |
| 45 | + } |
| 46 | + add(data) { |
| 47 | + const vertex = new Vertex(this, data); |
| 48 | + const key = data[this.keyField]; |
| 49 | + if (this.vertices.get(key) === undefined) { |
| 50 | + this.vertices.set(key, vertex); |
| 51 | + } |
| 52 | + return vertex; |
| 53 | + } |
| 54 | + select(query) { |
| 55 | + const vertices = new Set(); |
| 56 | + let vertex, condition, data, field; |
| 57 | + for (vertex of this.vertices.values()) { |
| 58 | + condition = true; |
| 59 | + data = vertex.data; |
| 60 | + if (data) { |
| 61 | + for (field in query) { |
| 62 | + condition = condition && data[field] === query[field]; |
| 63 | + } |
| 64 | + if (condition) vertices.add(vertex); |
| 65 | + } |
| 66 | + } |
| 67 | + return new Cursor(vertices); |
| 68 | + } |
| 69 | +} |
| 70 | + |
| 71 | +// Usage |
| 72 | + |
| 73 | +const graph = new Graph('name'); |
| 74 | + |
| 75 | +const marcus = graph.add( |
| 76 | + { name: 'Marcus Aurelius', city: 'Rome', born: 121, dynasty: 'Antonine' } |
| 77 | +); |
| 78 | +const lucius = graph.add( |
| 79 | + { name: 'Lucius Verus', city: 'Rome', born: 130, dynasty: 'Antonine' } |
| 80 | +); |
| 81 | +const pius = graph.add( |
| 82 | + { name: 'Antoninus Pius', city: 'Lanuvium', born: 86, dynasty: 'Antonine' } |
| 83 | +); |
| 84 | +const hadrian = graph.add( |
| 85 | + { name: 'Hadrian', city: 'Santiponce', born: 76, dynasty: 'Nerva–Trajan' } |
| 86 | +); |
| 87 | +const trajan = graph.add( |
| 88 | + { name: 'Trajan', city: 'Sevilla', born: 98, dynasty: 'Nerva–Trajan' } |
| 89 | +); |
| 90 | + |
| 91 | +marcus.link(lucius); |
| 92 | +lucius.link(trajan, marcus, marcus, marcus); |
| 93 | +pius.link(marcus, lucius); |
| 94 | +hadrian.link(trajan); |
| 95 | +trajan.link(lucius, marcus); |
| 96 | + |
| 97 | +console.dir({ graph }, { depth: null }); |
| 98 | + |
| 99 | +const res = graph |
| 100 | + .select({ city: 'Rome', dynasty: 'Antonine' }) |
| 101 | + .linked('Trajan'); |
| 102 | + |
| 103 | +console.log('\nQuery result:\n'); |
| 104 | +for (const item of res.vertices) { |
| 105 | + console.dir(item.data); |
| 106 | +} |
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