topological-sort-group/dist/esm/cycles.js

Topological sorting and cycle detection. Optional grouping for parallel processing

export default function cycles(graph) {
    const visited = {};
    const marks = {};
    const cycles = [];
    function visit(key, ancestors) {
        if (marks[key]) return cycles.push(ancestors.concat(key)); // found a cycle
        if (visited[key]) return; // already visited
        visited[key] = true;
        // check for cycles from this key
        marks[key] = true;
        graph.edges(key).forEach((neighborKey)=>{
            visit(neighborKey, ancestors.concat(key));
        });
        delete marks[key];
    }
    // check all keys
    let keys = graph.keys();
    while(keys.length > 0){
        visit(keys[0], []);
        // remove processed
        keys = keys.filter((key)=>!visited[key]);
    }
    return cycles;
}