What is dependency-graph?
The dependency-graph npm package is a simple library for creating a directed graph of dependencies and performing operations on it. It allows for adding nodes and dependencies, detecting cycles, and performing depth-first searches among other functionalities. This package is particularly useful for managing and analyzing dependencies in software projects, ensuring that dependency structures are acyclic and well-organized.
What are dependency-graph's main functionalities?
Creating a Dependency Graph
This feature allows for the creation of a new dependency graph and the addition of nodes and dependencies between them. In the code sample, a graph is created, and two nodes, 'A' and 'B', are added with a dependency from 'A' to 'B'.
const { DepGraph } = require('dependency-graph');
const graph = new DepGraph();
graph.addNode('A');
graph.addNode('B');
graph.addDependency('A', 'B');
Detecting Cycles
This feature checks if the dependency graph contains any cycles, which are sequences of dependencies that loop back on themselves. The code sample demonstrates how to check if the graph has any cycles.
const hasCycle = graph.hasCycle();
Performing Depth-First Search
This feature performs a depth-first search to find all dependencies of a given node. The code sample shows how to find all dependencies of node 'A'. This is useful for understanding the full set of dependencies that a particular node or module relies on.
const dependenciesOfA = graph.dependenciesOf('A');
Other packages similar to dependency-graph
madge
Madge is a tool for generating a visual graph of module dependencies, also capable of finding circular dependencies. It is more focused on visualization and analysis of large codebases, making it a bit more comprehensive for those specific needs compared to dependency-graph.
toposort
Toposort is another npm package that focuses on sorting nodes in a directed graph topologically. While dependency-graph provides broad functionalities for managing and analyzing dependencies, toposort specializes in the sorting aspect, which is useful for determining the order of tasks or module loading.
Dependency Graph
Simple dependency graph
Overview
This is a simple dependency graph useful for determining the order to do a list of things that depend on certain items being done before they are.
To use, npm install dependency-graph
and then require('dependency-graph').DepGraph
API
DepGraph
Nodes in the graph are just simple strings with optional data associated with them.
addNode(name, data)
- add a node in the graph with optional data. If data
is not given, name
will be used as dataremoveNode(name)
- remove a node from the graphhasNode(name)
- check if a node exists in the graphgetNodeData(name)
- get the data associated with a node (will throw an Error if the node does not exist)setNodeData(name, data)
- set the data for an existing node (will throw an Error if the node does not exist)addDependency(from, to)
- add a dependency between two nodes (will throw an Error if one of the nodes does not exist)removeDependency(from, to)
- remove a dependency between two nodesdependenciesOf(name, leavesOnly)
- get an array containing the nodes that the specified node depends on (transitively). If leavesOnly
is true, only nodes that do not depend on any other nodes will be returned in the array.dependantsOf(name, leavesOnly)
- get an array containing the nodes that depend on the specified node (transitively). If leavesOnly
is true, only nodes that do not have any dependants will be returned in the array.overallOrder(leavesOnly)
- construct the overall processing order for the dependency graph. If leavesOnly
is true, only nodes that do not depend on any other nodes will be returned.
Dependency Cycles are detected when running dependenciesOf
, dependantsOf
, and overallOrder
and if one is found, an error will be thrown that includes what the cycle was in the message: e.g. Dependency Cycle Found: a -> b -> c -> a
.
Examples
var DepGraph = require('dependency-graph').DepGraph;
var graph = new DepGraph();
graph.addNode('a');
graph.addNode('b');
graph.addNode('c');
graph.addDependency('a', 'b');
graph.addDependency('b', 'c');
graph.dependenciesOf('a'); // ['c', 'b']
graph.dependenciesOf('b'); // ['c']
graph.dependantsOf('c'); // ['a', 'b']
graph.overallOrder(); // ['c', 'b', 'a']
graph.overallOrder(true); // ['c']
graph.addNode('d', 'data');
graph.getNodeData('d'); // 'data'
graph.setNodeData('d', 'newData');
graph.getNodeData('d'); // 'newData'