@grouparoo/core/dist/modules/topologicalSort.js

The Grouparoo Core

"use strict";
// From https://jeremyckahn.github.io/javascript-algorithms/graphs_others_topological-sort.js.html (with modifications)
// Learn more @ https://en.wikipedia.org/wiki/Topological_sorting
Object.defineProperty(exports, "__esModule", { value: true });
exports.topologicalSort = void 0;
/**
 * Topological sort algorithm of a directed acyclic graph.<br><br>
 * Time complexity: O(|E| + |V|) where E is a number of edges
 * and |V| is the number of nodes.
 *
 * @public
 * @param {Array} Graph Adjacency list, which represents the graph.
 * @returns {Array} Ordered vertices.
 *
 * @example
 * var topsort =
 *  require('path-to-algorithms/src/graphs/' +
 * 'others/topological-sort').topologicalSort;
 * var graph = {
 *     v1: ['v2', 'v5'],
 *     v2: [],
 *     v3: ['v1', 'v2', 'v4', 'v5'],
 *     v4: [],
 *     v5: []
 * };
 * var vertices = topologicalSort(graph); // ['v3', 'v4', 'v1', 'v5', 'v2']
 */
function topologicalSort(graph) {
    const result = [];
    const errors = [];
    const visited = {};
    const temp = {};
    for (const node in graph) {
        if (!visited[node] && !temp[node]) {
            topologicalSortHelper(node, visited, temp, graph, result, errors);
        }
    }
    if (errors.length > 0)
        throw new Error(errors.join("\n"));
    return result;
}
exports.topologicalSort = topologicalSort;
function topologicalSortHelper(node, visited, temp, graph, result, errors) {
    temp[node] = true;
    const neighbors = graph[node];
    if (!neighbors) {
        errors.push(`unknownNodeId ${node}`);
        return;
    }
    for (let i = 0; i < neighbors.length; i += 1) {
        const n = neighbors[i];
        if (temp[n])
            errors.push("The graph is not a DAG");
        if (!visited[n])
            topologicalSortHelper(n, visited, temp, graph, result, errors);
    }
    temp[node] = false;
    visited[node] = true;
    result.push(node);
}