1 files changed, 94 insertions, 0 deletions
diff --git a/deps/npm/node_modules/@npmcli/arborist/lib/calc-dep-flags.js b/deps/npm/node_modules/@npmcli/arborist/lib/calc-dep-flags.js
new file mode 100644
index 0000000000..73f1e60d7c
--- /dev/null
+++ b/deps/npm/node_modules/@npmcli/arborist/lib/calc-dep-flags.js
@@ -0,0 +1,94 @@
+const { depth } = require('treeverse')
+
+const calcDepFlags = (tree, resetRoot = true) => {
+  if (resetRoot) {
+    tree.dev = false
+    tree.optional = false
+    tree.devOptional = false
+    tree.peer = false
+  }
+  const ret = depth({
+    tree,
+    visit: node => calcDepFlagsStep(node),
+    filter: node => node,
+    getChildren: node => [...node.edgesOut.values()].map(edge => edge.to),
+  })
+  return ret
+}
+
+const calcDepFlagsStep = (node) => {
+  // This rewalk is necessary to handle cases where devDep and optional
+  // or normal dependency graphs overlap deep in the dep graph.
+  // Since we're only walking through deps that are not already flagged
+  // as non-dev/non-optional, it's typically a very shallow traversal
+  node.extraneous = false
+
+  // for links, map their hierarchy appropriately
+  if (node.target) {
+    node.target.dev = node.dev
+    node.target.optional = node.optional
+    node.target.devOptional = node.devOptional
+    node.target.peer = node.peer
+    node.target.extraneous = false
+    node = node.target
+  }
+
+  node.edgesOut.forEach(({peer, optional, dev, to}) => {
+    // if the dep is missing, then its flags are already maximally unset
+    if (!to)
+      return
+
+    // everything with any kind of edge into it is not extraneous
+    to.extraneous = false
+
+    // devOptional is the *overlap* of the dev and optional tree.
+    // however, for convenience and to save an extra rewalk, we leave
+    // it set when we are in *either* tree, and then omit it from the
+    // package-lock if either dev or optional are set.
+    const unsetDevOpt = !node.devOptional && !node.dev && !node.optional &&
+      !dev && !optional
+
+    // if we are not in the devOpt tree, then we're also not in
+    // either the dev or opt trees
+    const unsetDev = unsetDevOpt || !node.dev && !dev
+    const unsetOpt = unsetDevOpt ||
+      !node.optional && !optional
+    const unsetPeer = !node.peer && !peer
+
+    if (unsetPeer)
+      unsetFlag(to, 'peer')
+
+    if (unsetDevOpt)
+      unsetFlag(to, 'devOptional')
+
+    if (unsetDev)
+      unsetFlag(to, 'dev')
+
+    if (unsetOpt)
+      unsetFlag(to, 'optional')
+  })
+
+  return node
+}
+
+// typically a short walk, since it only traverses deps that
+// have the flag set.
+const unsetFlag = (node, flag) => {
+  if (node[flag]) {
+    node[flag] = false
+    depth({
+      tree: node,
+      visit: node => {
+        node.extraneous = node[flag] = false
+        if (node.target)
+          node.target.extraneous = node.target[flag] = false
+      },
+      getChildren: node => [...(node.target || node).edgesOut.values()]
+        .filter(edge => edge.to && edge.to[flag] &&
+          (flag !== 'peer' && edge.type === 'peer' || edge.type === 'prod'))
+        .map(edge => edge.to),
+    })
+  }
+}
+
+module.exports = calcDepFlags