gaia-tsort

Topological sort utility for directed acyclic graphs.

Installation

Node.js

gaia-tsort is available on npm.

$ npm install gaia-tsort

Component

gaia-tsort is available as a component.

$ component install qualiancy/gaia-tsort

Usage

tsort (edges)

• @param {Array} edges
• @return {Object}

Topological sorting is a methodology used to organize a directed-acyclic-graph (DAG). A DAG is a graph of nodes in which there are no cyclic references, and therefor has a specific starting and ending point.

A set of edges is defined as an array, with each element being an array of x, y pairs, where x is a parent of y.

var edges = [
    [ 'a', 'b' ]
  , [ 'a', 'c' ]
  , [ 'd', 'e' ]
  , [ 'b', 'd' ]
];

With the above edges, we expect a to be the top-most parent. b and c are it's children; d is a child of b; e is a child of d.

The following demonstrates the output of this tool.

var tsort = require('gaia-tsort')
  , sorted = tsort(edges);
 
// console.log(sorted);
{
    path: [ 'a', 'c', 'b', 'd', 'e' ]
  , graph: [
        { id: 'a', children: [ 'b', 'c' ], parents: [] }
      , { id: 'c', children: [], parents: [ 'a' ] }
      , { id: 'b', children: [ 'd' ], parents: [ 'a' ] }
      , { id: 'd', children: [ 'e' ], parents: [ 'b' ] }
      , { id: 'e', children: [], parents: [ 'd' ] }
    ]
}

Should there a cyclical reference, the result will resemble the following.

{
  error: new Error('child-name can not come before parent-name')
}

License

(The MIT License)

Copyright (c) 2012 Jake Luer jake@qualiancy.com (http://qualiancy.com)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.