@phosphor/algorithm
Version:
PhosphorJS - Algorithms and Iterators
72 lines (71 loc) • 2.15 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
/*-----------------------------------------------------------------------------
| Copyright (c) 2014-2017, PhosphorJS Contributors
|
| Distributed under the terms of the BSD 3-Clause License.
|
| The full license is in the file LICENSE, distributed with this software.
|----------------------------------------------------------------------------*/
var iter_1 = require("./iter");
/**
* Topologically sort an iterable of edges.
*
* @param edges - The iterable or array-like object of edges to sort.
* An edge is represented as a 2-tuple of `[fromNode, toNode]`.
*
* @returns The topologically sorted array of nodes.
*
* #### Notes
* If a cycle is present in the graph, the cycle will be ignored and
* the return value will be only approximately sorted.
*
* #### Example
* ```typescript
* import { topologicSort } from '@phosphor/algorithm';
*
* let data = [
* ['d', 'e'],
* ['c', 'd'],
* ['a', 'b'],
* ['b', 'c']
* ];
*
* topologicSort(data); // ['a', 'b', 'c', 'd', 'e']
*/
function topologicSort(edges) {
// Setup the shared sorting state.
var sorted = [];
var visited = new Set();
var graph = new Map();
// Add the edges to the graph.
iter_1.each(edges, addEdge);
// Visit each node in the graph.
graph.forEach(function (v, k) { visit(k); });
// Return the sorted results.
return sorted;
// Add an edge to the graph.
function addEdge(edge) {
var fromNode = edge[0], toNode = edge[1];
var children = graph.get(toNode);
if (children) {
children.push(fromNode);
}
else {
graph.set(toNode, [fromNode]);
}
}
// Recursively visit the node.
function visit(node) {
if (visited.has(node)) {
return;
}
visited.add(node);
var children = graph.get(node);
if (children) {
children.forEach(visit);
}
sorted.push(node);
}
}
exports.topologicSort = topologicSort;