Initiatives: create plugin declaration

Including feedback/fixes from #1416
- Rephrased comment.

src/plugins/initiatives/declaration.js

@@ -0,0 +1,103 @@
+// @flow
+
+import deepFreeze from "deep-freeze";
+import type {PluginDeclaration} from "../../analysis/pluginDeclaration";
+import type {NodeType, EdgeType} from "../../analysis/types";
+import {NodeAddress, EdgeAddress} from "../../core/graph";
+
+export const nodePrefix = NodeAddress.fromParts(["sourcecred", "initiatives"]);
+export const edgePrefix = EdgeAddress.fromParts(["sourcecred", "initiatives"]);
+
+export const initiativeNodeType: NodeType = deepFreeze({
+  name: "Initiative",
+  pluralName: "Initiatives",
+  prefix: NodeAddress.append(nodePrefix, "initiative"),
+  defaultWeight: 1,
+  description:
+    "An initiative supernode, describing a scoped improvement to a project from proposal to completion.",
+});
+
+/*
+	Note on the forward and backward naming convention.
+	It follows the core/graph.js documentation to use
+	a <subject> <verb> <object> format to figure out
+	the directionality.
+*/
+
+/**
+ * An initiative (src) DEPENDS ON (verb) a dependency (dst).
+ * Forward: depending on something shows the value of the dependency.
+ * Backward: having a dependency does not endorse the iniative, but does flow
+ * some cred to incentivize reuse and attribution.
+ */
+export const dependsOnEdgeType: EdgeType = deepFreeze({
+  forwardName: "depends on",
+  backwardName: "is a dependency for",
+  prefix: EdgeAddress.append(edgePrefix, "dependsOn"),
+  defaultWeight: {forwards: 1, backwards: 1 / 16},
+  description: "Connects an initiative to it's dependencies.",
+});
+
+/**
+ * An initiative (src) REFERENCES (verb) a reference (dst).
+ * Forward: referencing from an initiative shows the value of the reference.
+ * But we assume a reference likely needs some refinement to be used by the initiative,
+ * so it flows less cred than to a dependency.
+ * Backward: having reference material does not endorse the iniative, but does flow
+ * some cred to incentivize using existing research and attribution.
+ */
+export const referencesEdgeType: EdgeType = deepFreeze({
+  forwardName: "references",
+  backwardName: "is referenced for",
+  prefix: EdgeAddress.append(edgePrefix, "references"),
+  defaultWeight: {forwards: 1 / 2, backwards: 1 / 16},
+  description: "Connects an initiative to it's references.",
+});
+
+/**
+ * A contribution (src) CONTRIBUTES TO (verb) an initiative (dst).
+ * Forward: a contribution towards the initiative is also an endorsement of the
+ * value of that initiative.
+ * Backward: an initiative in large part consists of it's contributions, so the
+ * value of an initiative caries over to it's contributions.
+ */
+export const contributesToEdgeType: EdgeType = deepFreeze({
+  forwardName: "contributes to",
+  backwardName: "is contributed to by",
+  prefix: EdgeAddress.append(edgePrefix, "contributesTo"),
+  defaultWeight: {forwards: 1, backwards: 1},
+  description: "Connects an initiative to it's contributions.",
+});
+
+/**
+ * A user (src) CHAMPIONS (verb) an initiative (dst).
+ * Meaning forward is the user claiming and committing they will champion an
+ * initiative. And backward is the return of cred based on the completion and
+ * succesful championing of the ininiative.
+ *
+ * Forward: a user championing an iniative is also an endorsement of the value
+ * of that initiative.
+ * Backward: an initiative likely received a lot of ongoing support from it's
+ * champion. We're assuming this is more support than individual contributions.
+ */
+export const championsEdgeType: EdgeType = deepFreeze({
+  forwardName: "champions",
+  backwardName: "is championed by",
+  prefix: EdgeAddress.append(edgePrefix, "champions"),
+  defaultWeight: {forwards: 1, backwards: 4},
+  description: "Connects an initiative to users who champion it.",
+});
+
+export const declaration: PluginDeclaration = deepFreeze({
+  name: "Initiatives",
+  nodePrefix,
+  edgePrefix,
+  nodeTypes: [initiativeNodeType],
+  edgeTypes: [
+    dependsOnEdgeType,
+    referencesEdgeType,
+    contributesToEdgeType,
+    championsEdgeType,
+  ],
+  userTypes: [],
+});