From 44dea532b86909d64a91d40576feddbb98540bf9 Mon Sep 17 00:00:00 2001
From: Luca Pizzini <lpizzini7@gmail.com>
Date: Tue, 24 Jan 2023 09:34:45 +0100
Subject: [PATCH] feat: added Schema.prototype.omit() function

fix #12931
---
 lib/schema.js       | 42 +++++++++++++++++++++++++
 test/schema.test.js | 75 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/lib/schema.js b/lib/schema.js
index 20471d40e59..c77c27d03d5 100644
--- a/lib/schema.js
+++ b/lib/schema.js
@@ -478,6 +478,48 @@ Schema.prototype.pick = function(paths, options) {
   return newSchema;
 };
 
+/**
+ * Returns a new schema that has the `paths` from the original schema, minus the omitted ones.
+ *
+ * This method is analagous to [Lodash's `omit()` function](https://lodash.com/docs/#omit) for Mongoose schemas.
+ *
+ * #### Example:
+ *
+ *     const schema = Schema({ name: String, age: Number });
+ *     // Creates a new schema omitting the `age` path
+ *     const newSchema = schema.omit(['age']);
+ *
+ *     newSchema.path('name'); // SchemaString { ... }
+ *     newSchema.path('age'); // undefined
+ *
+ * @param {String[]} paths List of Paths to omit for the new Schema
+ * @param {Object} [options] Options to pass to the new Schema Constructor (same as `new Schema(.., Options)`). Defaults to `this.options` if not set.
+ * @return {Schema}
+ * @api public
+ */
+
+Schema.prototype.omit = function(paths, options) {
+  const newSchema = new Schema(this, options || this.options);
+  if (!Array.isArray(paths)) {
+    throw new MongooseError(
+      'Schema#omit() only accepts an array argument, ' +
+        'got "' +
+        typeof paths +
+        '"'
+    );
+  }
+
+  newSchema.remove(paths);
+
+  for (const nested in newSchema.singleNestedPaths) {
+    if (paths.includes(nested)) {
+      delete newSchema.singleNestedPaths[nested];
+    }
+  }
+
+  return newSchema;
+};
+
 /**
  * Returns default options for this schema, merged with `options`.
  *
diff --git a/test/schema.test.js b/test/schema.test.js
index dec8be82d56..f5934e2a821 100644
--- a/test/schema.test.js
+++ b/test/schema.test.js
@@ -2339,6 +2339,81 @@ describe('schema', function() {
     });
   });
 
+  describe('omit() (gh-12931)', function() {
+    it('works with nested paths', function() {
+      const schema = Schema({
+        name: {
+          first: {
+            type: String,
+            required: true
+          },
+          last: {
+            type: String,
+            required: true
+          }
+        },
+        age: {
+          type: Number,
+          index: true
+        }
+      });
+      assert.ok(schema.path('name.first'));
+      assert.ok(schema.path('name.last'));
+
+      let newSchema = schema.omit(['name.first']);
+      assert.ok(!newSchema.path('name.first'));
+      assert.ok(newSchema.path('age'));
+      assert.ok(newSchema.path('age').index);
+
+      newSchema = schema.omit(['age']);
+      assert.ok(newSchema.path('name.first'));
+      assert.ok(newSchema.path('name.first').required);
+      assert.ok(newSchema.path('name.last'));
+      assert.ok(newSchema.path('name.last').required);
+      assert.ok(!newSchema.path('age'));
+
+      newSchema = schema.omit(['name.last', 'age']);
+      assert.ok(newSchema.path('name.first'));
+      assert.ok(newSchema.path('name.first').required);
+      assert.ok(!newSchema.path('name.last'));
+      assert.ok(!newSchema.path('age'));
+    });
+
+    it('with single nested paths', function() {
+      const schema = Schema({
+        name: Schema({
+          first: {
+            type: String,
+            required: true
+          },
+          last: {
+            type: String,
+            required: true
+          }
+        }),
+        age: {
+          type: Number,
+          index: true
+        }
+      });
+      assert.ok(schema.path('name.first'));
+      assert.ok(schema.path('name.last'));
+
+      let newSchema = schema.omit(['age']);
+      assert.ok(newSchema.path('name.first'));
+      assert.ok(newSchema.path('name.first').required);
+      assert.ok(newSchema.path('name.last'));
+      assert.ok(newSchema.path('name.last').required);
+      assert.ok(!newSchema.path('age'));
+
+      newSchema = schema.omit(['name.last', 'age']);
+      assert.ok(newSchema.path('name.first'));
+      assert.ok(newSchema.path('name.first').required);
+      assert.ok(!newSchema.path('name.last'));
+      assert.ok(!newSchema.path('age'));
+    });
+  });
+
   describe('path-level custom cast (gh-8300)', function() {
     it('with numbers', function() {
       const schema = Schema({