feat: add support to filtering by workspaces

Adds support to a new `workspaces` option, that accepts an array of
strings, allowing users to filter the resulting fund info to a specific
set of workspaces and their dependencies.

Relates to: npm/statusboard#301

README.md

@@ -73,7 +73,10 @@ Options:
 - `countOnly`: Uses the tree-traversal logic from **npm fund** but skips over
 any obj definition and just returns an obj containing `{ length }` - useful for
 things such as printing a `6 packages are looking for funding` msg.
-- `path`: Location to current working directory
+- `workspaces`: `Array<String>` List of workspaces names to filter for,
+the result will only include a subset of the resulting tree that includes
+only the nodes that are children of the listed workspaces names.
+- `path`, `registry` and more [Arborist](https://github.com/npm/arborist/) options.
 
 ##### <a name="fund.readTree"></a> `> fund.readTree(tree, [opts]) -> Promise<Object>`
 

index.js

@@ -2,6 +2,7 @@
 
 const URL = require('url').URL
 const Arborist = require('@npmcli/arborist')
+const { resolve } = require('path')
 
 // supports object funding and string shorthand, or an array of these
 // if original was an array, returns an array; else returns the lone item
@@ -38,7 +39,27 @@ function isValidFunding (funding) {
 
 const empty = () => Object.create(null)
 
+const filterWorkspaces = (tree, opts) => {
+  if (opts && opts.workspaces && opts.workspaces.length) {
+    const workspaces = new Set(opts.workspaces)
+    const workspacesPaths =
+      new Set(opts.workspaces.map(w => resolve(opts.path, w)))
+
+    const isFiltered = node =>
+      workspaces.has(node.name) || workspacesPaths.has(node.target.path)
+
+    for (const edge of tree.edgesOut.values()) {
+      const node = edge.to
+
+      if (!node.isWorkspace || !isFiltered(node))
+        node.parent = null
+    }
+  }
+  return tree
+}
+
 function readTree (tree, opts) {
+  tree = filterWorkspaces(tree, opts)
   let packageWithFundingCount = 0
   const seen = new Set()
   const { countOnly } = opts || {}
@@ -174,8 +195,7 @@ function readTree (tree, opts) {
 
 async function read (opts) {
   const arb = new Arborist(opts)
-  const tree = await arb.loadActual()
-
+  const tree = await arb.loadActual(opts)
   return readTree(tree, opts)
 }
 

test.js

@@ -1,5 +1,6 @@
 'use strict'
 
+const { resolve } = require('path')
 const t = require('tap')
 const {
   read,
@@ -1261,3 +1262,110 @@ t.test('invalid funding objects', (t) => {
   )
   t.end()
 })
+
+t.test('workspaces', t => {
+  t.test('filter by workspace', async t => {
+    const path = t.testdir({
+      'package.json': JSON.stringify({
+        name: 'root',
+        version: '1.0.0',
+        workspaces: [
+          'packages/*',
+        ],
+        dependencies: {
+          '@npmcli/baz': '^1.0.0',
+        },
+      }),
+      packages: {
+        a: {
+          'package.json': JSON.stringify({
+            name: 'a',
+            version: '1.0.0',
+            funding: 'http://example.com/a',
+            dependencies: {
+              '@npmcli/foo': '^1.0.0',
+            },
+          }),
+        },
+        b: {
+          'package.json': JSON.stringify({
+            name: 'b',
+            version: '1.0.0',
+            devDependencies: {
+              '@npmcli/bar': '^1.0.0',
+            },
+          }),
+        },
+      },
+      node_modules: {
+        a: t.fixture('symlink', '../packages/a'),
+        b: t.fixture('symlink', '../packages/b'),
+        '@npmcli': {
+          foo: {
+            'package.json': JSON.stringify({
+              name: '@npmcli/foo',
+              version: '1.0.0',
+              funding: 'http://example.com/foo',
+            }),
+          },
+          bar: {
+            'package.json': JSON.stringify({
+              name: '@npmcli/bar',
+              version: '1.0.0',
+              funding: 'http://example.com/bar',
+            }),
+          },
+          baz: {
+            'package.json': JSON.stringify({
+              name: '@npmcli/baz',
+              version: '1.0.0',
+              funding: 'http://example.com/baz',
+            }),
+          },
+        },
+      },
+    })
+
+    const expected = {
+      dependencies: {
+        a: {
+          funding: {
+            url: 'http://example.com/a',
+          },
+          version: '1.0.0',
+          dependencies: {
+            '@npmcli/foo': {
+              funding: {
+                url: 'http://example.com/foo',
+              },
+              version: '1.0.0',
+            },
+          },
+        },
+      },
+      length: 2,
+      name: 'root',
+      version: '1.0.0',
+    }
+
+    t.same(
+      await read({ path, workspaces: ['a'] }),
+      expected,
+      'should filter by workspace name'
+    )
+
+    t.same(
+      await read({ path, workspaces: ['./packages/a'] }),
+      expected,
+      'should filter by workspace path'
+    )
+
+    t.same(
+      await read({ path, workspaces: [resolve(path, 'packages/a')] }),
+      expected,
+      'should filter by workspace full path'
+    )
+  })
+
+  t.end()
+})