perf(gatsby): Eliminate generator (gatsbyjs#20102)

pvdz · web-flow · commit c3ca41a75cf8 · 2019-12-17T09:49:29.000+01:00
* perf(gatsby): Eliminate generator

The generator eliminated by this commit was working fine but felt a little redundant. And since it was ranking at the top of the perf chart, I changed it to a plain `forEach` loop, which dropped it from the benchmark chart.

Additionally dropped two `Array.from` because they were redundant.
diff --git a/packages/gatsby/src/redux/nodes.js b/packages/gatsby/src/redux/nodes.js
@@ -103,26 +103,20 @@ exports.saveResolvedNodes = async (nodeTypeNames, resolver) => {
   }
 }
 
-const getNodesAndResolvedNodes = typeName => {
+const addResolvedNodes = (typeName, arr) => {
   const { nodesByType, resolvedNodesCache } = store.getState()
-  const nodes = nodesByType.get(typeName)
-  if (nodes) {
-    const resolvedNodes = resolvedNodesCache.get(typeName)
+  const nodes /*: Map<mixed> */ = nodesByType.get(typeName)
+
+  if (!nodes) return
+
+  const resolvedNodes = resolvedNodesCache.get(typeName)
+
+  nodes.forEach(node => {
     if (resolvedNodes) {
-      return Array.from(resolvedNodesIterator(nodes, resolvedNodes))
-    } else {
-      return Array.from(nodes.values())
+      node.__gatsby_resolved = resolvedNodes.get(node.id)
     }
-  } else {
-    return []
-  }
-}
-
-function* resolvedNodesIterator(nodes, resolvedNodes) {
-  for (const node of nodes.values()) {
-    node.__gatsby_resolved = resolvedNodes.get(node.id)
-    yield node
-  }
+    arr.push(node)
+  })
 }
 
-exports.getNodesAndResolvedNodes = getNodesAndResolvedNodes
+exports.addResolvedNodes = addResolvedNodes
diff --git a/packages/gatsby/src/redux/run-sift.js b/packages/gatsby/src/redux/run-sift.js
@@ -119,20 +119,13 @@ function handleMany(siftArgs, nodes, sort, resolvedFields) {
  *   if `firstOnly` is true
  */
 const runSift = (args: Object) => {
-  const { getNode, getNodesAndResolvedNodes } = require(`./nodes`)
+  const { getNode, addResolvedNodes } = require(`./nodes`)
 
   const { nodeTypeNames } = args
 
-  let nodes
+  let nodes = []
 
-  if (nodeTypeNames.length > 1) {
-    nodes = nodeTypeNames.reduce((acc, typeName) => {
-      acc.push(...getNodesAndResolvedNodes(typeName))
-      return acc
-    }, [])
-  } else {
-    nodes = getNodesAndResolvedNodes(nodeTypeNames[0])
-  }
+  nodeTypeNames.forEach(typeName => addResolvedNodes(typeName, nodes))
 
   return runSiftOnNodes(nodes, args, getNode)
 }
