diff --git a/src/app/credExplorer/WeightConfig.js b/src/app/credExplorer/WeightConfig.js
index 4f2830b..977055a 100644
--- a/src/app/credExplorer/WeightConfig.js
+++ b/src/app/credExplorer/WeightConfig.js
@@ -3,7 +3,7 @@
 import React from "react";
 
 import {type EdgeEvaluator} from "../../core/attribution/pagerank";
-import {byEdgeType, byNodeType} from "./edgeWeights";
+import {weightsToEdgeEvaluator} from "./weights/weightsToEdgeEvaluator";
 import type {StaticAdapterSet} from "../adapters/adapterSet";
 import {
   type WeightedTypes,
@@ -104,18 +104,8 @@ export class WeightConfig extends React.Component<Props, State> {
       edgeWeights = edgeWeights.concat(newEdgeWeights);
     }
 
-    const edgePrefixes = edgeWeights.map(
-      ({type, forwardWeight, backwardWeight}) => ({
-        prefix: type.prefix,
-        forwardWeight,
-        backwardWeight,
-      })
-    );
-    const nodePrefixes = nodeWeights.map(({type, weight}) => ({
-      prefix: type.prefix,
-      weight,
-    }));
-    const edgeEvaluator = byNodeType(byEdgeType(edgePrefixes), nodePrefixes);
+    const weights = {nodes: nodeWeights, edges: edgeWeights};
+    const edgeEvaluator = weightsToEdgeEvaluator(weights);
     this.props.onChange(edgeEvaluator);
   }
 }
diff --git a/src/app/credExplorer/edgeWeights.js b/src/app/credExplorer/edgeWeights.js
deleted file mode 100644
index bc63519..0000000
--- a/src/app/credExplorer/edgeWeights.js
+++ /dev/null
@@ -1,47 +0,0 @@
-// @flow
-import {
-  type Edge,
-  type EdgeAddressT,
-  type NodeAddressT,
-} from "../../core/graph";
-import {NodeTrie, EdgeTrie} from "../../core/trie";
-import type {EdgeEvaluator} from "../../core/attribution/pagerank";
-
-export function byEdgeType(
-  prefixes: $ReadOnlyArray<{|
-    +prefix: EdgeAddressT,
-    +forwardWeight: number,
-    +backwardWeight: number,
-  |}>
-): EdgeEvaluator {
-  const trie = new EdgeTrie();
-  for (const {prefix, forwardWeight, backwardWeight} of prefixes) {
-    trie.add(prefix, {toWeight: forwardWeight, froWeight: backwardWeight});
-  }
-  return function evaluator(edge: Edge) {
-    return trie.getLast(edge.address);
-  };
-}
-
-export function byNodeType(
-  base: EdgeEvaluator,
-  prefixes: $ReadOnlyArray<{|
-    +prefix: NodeAddressT,
-    +weight: number,
-  |}>
-): EdgeEvaluator {
-  const trie = new NodeTrie();
-  for (const {weight, prefix} of prefixes) {
-    trie.add(prefix, weight);
-  }
-  return function evaluator(edge: Edge) {
-    const srcWeight = trie.getLast(edge.src);
-    const dstWeight = trie.getLast(edge.dst);
-
-    const baseResult = base(edge);
-    return {
-      toWeight: dstWeight * baseResult.toWeight,
-      froWeight: srcWeight * baseResult.froWeight,
-    };
-  };
-}
diff --git a/src/app/credExplorer/weights/weightsToEdgeEvaluator.js b/src/app/credExplorer/weights/weightsToEdgeEvaluator.js
new file mode 100644
index 0000000..fd373dc
--- /dev/null
+++ b/src/app/credExplorer/weights/weightsToEdgeEvaluator.js
@@ -0,0 +1,27 @@
+// @flow
+
+import type {Edge} from "../../../core/graph";
+import type {WeightedTypes} from "./PluginWeightConfig";
+import type {EdgeEvaluator} from "../../../core/attribution/pagerank";
+import {NodeTrie, EdgeTrie} from "../../../core/trie";
+
+export function weightsToEdgeEvaluator(weights: WeightedTypes): EdgeEvaluator {
+  const nodeTrie = new NodeTrie();
+  for (const {type, weight} of weights.nodes) {
+    nodeTrie.add(type.prefix, weight);
+  }
+  const edgeTrie = new EdgeTrie();
+  for (const {type, forwardWeight, backwardWeight} of weights.edges) {
+    edgeTrie.add(type.prefix, {forwardWeight, backwardWeight});
+  }
+
+  return function evaluator(edge: Edge) {
+    const srcWeight = nodeTrie.getLast(edge.src);
+    const dstWeight = nodeTrie.getLast(edge.dst);
+    const {forwardWeight, backwardWeight} = edgeTrie.getLast(edge.address);
+    return {
+      toWeight: dstWeight * forwardWeight,
+      froWeight: srcWeight * backwardWeight,
+    };
+  };
+}
diff --git a/src/app/credExplorer/weights/weightsToEdgeEvaluator.test.js b/src/app/credExplorer/weights/weightsToEdgeEvaluator.test.js
new file mode 100644
index 0000000..2668eab
--- /dev/null
+++ b/src/app/credExplorer/weights/weightsToEdgeEvaluator.test.js
@@ -0,0 +1,96 @@
+// @flow
+
+import * as NullUtil from "../../../util/null";
+import {
+  fallbackNodeType,
+  fallbackEdgeType,
+} from "../../adapters/fallbackAdapter";
+import {
+  inserterNodeType,
+  machineNodeType,
+  assemblesEdgeType,
+  factorioEdges,
+} from "../../adapters/demoAdapters";
+import {weightsToEdgeEvaluator} from "./weightsToEdgeEvaluator";
+
+describe("app/credExplorer/weights/weightsToEdgeEvaluator", () => {
+  describe("weightsToEdgeEvaluator", () => {
+    type WeightArgs = {|
+      +assemblesForward?: number,
+      +assemblesBackward?: number,
+      +baseForward?: number,
+      +baseBackward?: number,
+      +inserter?: number,
+      +machine?: number,
+      +baseNode?: number,
+    |};
+    function weights({
+      assemblesForward,
+      assemblesBackward,
+      baseForward,
+      baseBackward,
+      inserter,
+      machine,
+      baseNode,
+    }: WeightArgs) {
+      const nodes = [
+        {weight: NullUtil.orElse(inserter, 1), type: inserterNodeType},
+        {weight: NullUtil.orElse(machine, 1), type: machineNodeType},
+        {weight: NullUtil.orElse(baseNode, 1), type: fallbackNodeType},
+      ];
+      const edges = [
+        {
+          forwardWeight: NullUtil.orElse(assemblesForward, 1),
+          backwardWeight: NullUtil.orElse(assemblesBackward, 1),
+          type: assemblesEdgeType,
+        },
+        {
+          forwardWeight: NullUtil.orElse(baseForward, 1),
+          backwardWeight: NullUtil.orElse(baseBackward, 1),
+          type: fallbackEdgeType,
+        },
+      ];
+      return {nodes, edges};
+    }
+    function exampleEdgeWeights(weightArgs: WeightArgs) {
+      const ws = weights(weightArgs);
+      const ee = weightsToEdgeEvaluator(ws);
+      // src is a machine, dst is an inserter, edge type is assembles
+      return ee(factorioEdges.assembles1);
+    }
+    it("toWeight is affected by the edge's forwardWeight", () => {
+      expect(exampleEdgeWeights({assemblesForward: 2}).toWeight).toEqual(2);
+    });
+    it("froWeight is affected by the edge's backwardWeight", () => {
+      expect(exampleEdgeWeights({assemblesBackward: 3}).froWeight).toEqual(3);
+    });
+    it("toWeight is affected by the dst's weight", () => {
+      expect(exampleEdgeWeights({inserter: 4}).toWeight).toEqual(4);
+    });
+    it("froWeight is affected by the src's weight", () => {
+      expect(exampleEdgeWeights({machine: 5}).froWeight).toEqual(5);
+    });
+    it("only the closest-matching node prefix is considered", () => {
+      expect(exampleEdgeWeights({baseNode: 6})).toEqual({
+        toWeight: 1,
+        froWeight: 1,
+      });
+    });
+    it("only the closest-matching edge prefix is considered", () => {
+      expect(exampleEdgeWeights({baseBackward: 7})).toEqual({
+        toWeight: 1,
+        froWeight: 1,
+      });
+    });
+    it("node and edge weights compose via multiplication", () => {
+      expect(
+        exampleEdgeWeights({
+          inserter: 2,
+          machine: 3,
+          assemblesForward: 4,
+          assemblesBackward: 5,
+        })
+      ).toEqual({toWeight: 8, froWeight: 15});
+    });
+  });
+});