[bug#51838] [PATCH v6 05/41] guix: node-build-system: Add 'delete-dependencies' helper function.

[Philip McGrath]

* guix/build/node-build-system.scm (delete-dependencies): New exported
procedure.  Functionally updates a "package.json"-like value by removing
specified npm packages from the "dependencies" and "devDependencies"
objects.
---
 guix/build/node-build-system.scm | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/guix/build/node-build-system.scm b/guix/build/node-build-system.scm
index dc8b6a41c2..9967223b86 100644
--- a/guix/build/node-build-system.scm
+++ b/guix/build/node-build-system.scm
@@ -27,6 +27,7 @@ (define-module (guix build node-build-system)
   #:use-module (srfi srfi-1)
   #:export (%standard-phases
             with-atomic-json-file-replacement
+            delete-dependencies
             node-build))
 
 ;; Commentary:
@@ -325,6 +326,23 @@ (define resolve-dependencies
                                deps))))))
   #t)
 
+(define (delete-dependencies pkg-meta absent-dependencies)
+  "Functionally update PKG-META, a json object corresponding to a
+'package.json' file, to allow building without the ABSENT-DEPENDENCIES.  To
+avoid reintroducing the ABSENT-DEPENDENCIES, only use this procedure after the
+'patch-dependencies' phase."
+  (define delete-fom-jsobject
+    (match-lambda
+      (('@ . alist)
+       (cons '@ (filter (match-lambda
+                          ((k . v)
+                           (not (member k absent-dependencies))))
+                        alist)))))
+  (jsobject-update*
+   pkg-meta
+   "devDependencies" '(@) delete-fom-jsobject
+   "dependencies" '(@) delete-fom-jsobject))
+
 (define* (delete-lockfiles #:key inputs #:allow-other-keys)
   "Delete 'package-lock.json', 'yarn.lock', and 'npm-shrinkwrap.json', if they
 exist."
-- 
2.32.0