Add JSON writer / parser

webpro-patch · Sep 24, 2014 · 2cb6f49 · 2cb6f49
1 parent 7824897
commit 2cb6f49
Show file tree

Hide file tree

Showing 3 changed files with 131 additions and 0 deletions.
diff --git a/index.js b/index.js
@@ -31,4 +31,5 @@
 var _ = require("lodash");
 
 module.exports = _.clone(require("./lib"));
+module.exports.json = require("./lib/json");
 module.exports.alg = require("./lib/alg");
diff --git a/lib/json.js b/lib/json.js
@@ -0,0 +1,66 @@
+var _ = require("lodash"),
+    Graph = require("./Graph");
+
+module.exports = {
+  write: write,
+  read: read
+};
+
+function write(g) {
+  var json = {
+    options: {
+      directed: g.isDirected(),
+      multigraph: g.isMultigraph(),
+      compound: g.isCompound()
+    },
+    nodes: writeNodes(g),
+    edges: writeEdges(g)
+  };
+  if (!_.isUndefined(g.getGraph())) {
+    json.value = _.clone(g.getGraph());
+  }
+  return json;
+}
+
+function writeNodes(g) {
+  return _.map(g.nodes(), function(v) {
+    var nodeValue = g.getNode(v),
+        parent = g.getParent(v),
+        node = { v: v };
+    if (!_.isUndefined(nodeValue)) {
+      node.value = nodeValue;
+    }
+    if (!_.isUndefined(parent)) {
+      node.parent = parent;
+    }
+    return node;
+  });
+}
+
+function writeEdges(g) {
+  return _.map(g.edges(), function(e) {
+    var edgeValue = g.getEdge(e),
+        edge = { v: e.v, w: e.w };
+    if (!_.isUndefined(e.name)) {
+      edge.name = e.name;
+    }
+    if (!_.isUndefined(edgeValue)) {
+      edge.value = edgeValue;
+    }
+    return edge;
+  });
+}
+
+function read(json) {
+  var g = new Graph(json.options).setGraph(json.value);
+  _.each(json.nodes, function(entry) {
+    g.setNode(entry.v, entry.value);
+    if (entry.parent) {
+      g.setParent(entry.v, entry.parent);
+    }
+  });
+  _.each(json.edges, function(entry) {
+    g.setEdge({ v: entry.v, w: entry.w, name: entry.name }, entry.value);
+  });
+  return g;
+}
diff --git a/test/json-test.js b/test/json-test.js
@@ -0,0 +1,64 @@
+var expect = require("./chai").expect,
+    Graph = require("..").Graph,
+    read = require("..").json.read,
+    write = require("..").json.write;
+
+describe("json", function() {
+  it("preserves the graph options", function() {
+    expect(rw(new Graph({ directed: true })).isDirected()).to.be.true;
+    expect(rw(new Graph({ directed: false })).isDirected()).to.be.false;
+    expect(rw(new Graph({ multigraph: true })).isMultigraph()).to.be.true;
+    expect(rw(new Graph({ multigraph: false })).isMultigraph()).to.be.false;
+    expect(rw(new Graph({ compound: true })).isCompound()).to.be.true;
+    expect(rw(new Graph({ compound: false })).isCompound()).to.be.false;
+  });
+
+  it("preserves the graph value, if any", function() {
+    expect(rw(new Graph().setGraph(1)).getGraph()).equals(1);
+    expect(rw(new Graph().setGraph({ foo: "bar" })).getGraph()).eqls({ foo: "bar" });
+    expect(rw(new Graph()).getGraph()).to.be.undefined;
+  });
+
+  it("preserves nodes", function() {
+    expect(rw(new Graph().setNode("a")).hasNode("a")).to.be.true;
+    expect(rw(new Graph().setNode("a")).getNode("a")).to.be.undefined;
+    expect(rw(new Graph().setNode("a", 1)).getNode("a")).equals(1);
+    expect(rw(new Graph().setNode("a", { foo: "bar" })).getNode("a"))
+      .eqls({ foo: "bar" });
+  });
+
+  it("preserves simple edges", function() {
+    expect(rw(new Graph().setEdge("a", "b")).hasEdge("a", "b")).to.be.true;
+    expect(rw(new Graph().setEdge("a", "b")).getEdge("a", "b")).to.be.undefined;
+    expect(rw(new Graph().setEdge("a", "b", 1)).getEdge("a", "b")).equals(1);
+    expect(rw(new Graph().setEdge("a", "b", { foo: "bar" })).getEdge("a", "b"))
+      .eqls({ foo: "bar" });
+  });
+
+  it("preserves multi-edges", function() {
+    var g = new Graph({ multigraph: true });
+
+    g.setEdge({ v: "a", w: "b", name: "foo" });
+    expect(rw(g).hasEdge("a", "b", "foo")).to.be.true;
+
+    g.setEdge({ v: "a", w: "b", name: "foo" });
+    expect(rw(g).getEdge("a", "b", "foo")).to.be.undefined;
+
+    g.setEdge({ v: "a", w: "b", name: "foo" }, 1);
+    expect(rw(g).getEdge("a", "b", "foo")).equals(1);
+
+    g.setEdge({ v: "a", w: "b", name: "foo" }, { foo: "bar" });
+    expect(rw(g).getEdge("a", "b", "foo")).eqls({ foo: "bar" });
+  });
+
+  it("preserves parent / child relationships", function() {
+    expect(rw(new Graph({ compound: true }).setNode("a")).getParent("a"))
+      .to.be.undefined;
+    expect(rw(new Graph({ compound: true }).setParent("a", "parent")).getParent("a"))
+      .to.equal("parent");
+  });
+});
+
+function rw(g) {
+  return read(write(g));
+}