fix: npm ls <pkg> with depth cli config

Using the cli option --depth is currently not resulting in the expected
behavior of filtering depth level when running npm ls <pkg> - that's due
the special behavior of printing all results when using a filter arg.

This commit fixes it by adding support to limiting depth if a config
value is set by the user.

Fixes #1861

lib/ls.js

@@ -389,6 +389,8 @@ const ls = async (args) => {
   const only = npm.config.get('only')
   const prod = npm.config.get('prod')
   const production = npm.config.get('production')
+  const depthCli = // retrieves only user-defined values
+    npm.config.get('depth', 'cli') || npm.config.get('depth', 'user')
 
   const arb = new Arborist({
     global,
@@ -406,7 +408,12 @@ const ls = async (args) => {
   const seenItems = new Set()
   const seenNodes = new Map()
   const problems = new Set()
-  const depthToPrint = (all || args.length) ? Infinity : (depth || 0)
+
+  // defines special handling of printed depth when filtering with args
+  const filterDefaultDepth = depthCli === undefined ? Infinity : depthCli
+  const depthToPrint = (all || args.length)
+    ? filterDefaultDepth
+    : (depth || 0)
 
   // add root node of tree to list of seenNodes
   seenNodes.set(tree.path, tree)

tap-snapshots/test-lib-ls.js-TAP.test.js

@@ -373,6 +373,18 @@ [email protected] {CWD}/ls-ls-extraneous-deps
 
 `
 
+exports[`test/lib/ls.js TAP ls filter pkg arg using depth option > should list a in top-level only 1`] = `
+[email protected] {CWD}/ls-ls-filter-pkg-arg-using-depth-option
+\`-- [email protected]
+
+`
+
+exports[`test/lib/ls.js TAP ls filter pkg arg using depth option > should print empty results msg 1`] = `
+[email protected] {CWD}/ls-ls-filter-pkg-arg-using-depth-option
+\`-- (empty)
+
+`
+
 exports[`test/lib/ls.js TAP ls filtering by child of missing dep > should print tree and not duplicate child of missing items 1`] = `
 [email protected] {CWD}/ls-ls-filtering-by-child-of-missing-dep
 +-- [email protected] extraneous

test/lib/ls.js

@@ -1426,6 +1426,70 @@ t.test('ls', (t) => {
     })
   })
 
+  t.test('filter pkg arg using depth option', (t) => {
+    _flatOptions.depth = 0
+    prefix = t.testdir({
+      'package.json': JSON.stringify({
+        name: 'test-pkg-arg-filter-with-depth-opt',
+        version: '1.0.0',
+        dependencies: {
+          a: '^1.0.0',
+          b: '^1.0.0'
+        }
+      }),
+      node_modules: {
+        a: {
+          'package.json': JSON.stringify({
+            name: 'a',
+            version: '1.0.0'
+          })
+        },
+        b: {
+          'package.json': JSON.stringify({
+            name: 'b',
+            version: '1.0.0',
+            dependencies: {
+              c: '^1.0.0'
+            }
+          })
+        },
+        c: {
+          'package.json': JSON.stringify({
+            name: 'c',
+            version: '1.0.0',
+            dependencies: {
+              d: '^1.0.0'
+            }
+          })
+        },
+        d: {
+          'package.json': JSON.stringify({
+            name: 'd',
+            version: '1.0.0',
+            dependencies: {
+              a: '^1.0.0'
+            }
+          })
+        }
+      }
+    })
+
+    t.plan(4)
+    ls(['a'], (err) => {
+      t.ifError(err, 'should NOT have ELSPROBLEMS error code')
+      t.matchSnapshot(redactCwd(result), 'should list a in top-level only')
+
+      ls(['d'], (err) => {
+        t.ifError(err, 'should NOT have ELSPROBLEMS error code when filter')
+        t.matchSnapshot(redactCwd(result), 'should print empty results msg')
+      })
+    })
+  })
+
+  t.teardown(() => {
+    _flatOptions.depth = Infinity
+  })
+
   t.end()
 })