fix: added support for merging items into an existing array

lib/set.ts

@@ -67,6 +67,7 @@ function addToArray(
         getType(target[index]) === "object" &&
         getType(value) === "object"
     ) {
+        Object.assign(target[index], value);
         return [target[index], index, target, `${result[3]}/${index}}`];
     }
 
@@ -118,7 +119,10 @@ function create<T extends WorkingSet>(
         .map((r: QueryResult) => {
             const container = keyIsArray ? [] : {};
             const o = r[0];
-            if (Array.isArray(o)) {
+            const containerType = getType(container);
+            const itemType = getType(o[query]);
+
+            if (Array.isArray(o) && itemType !== containerType) {
                 return addToArray(r, query, container, force);
             }
             o[query] = o[query] || container;

test/unit/set.test.ts

@@ -1,7 +1,7 @@
 /* eslint object-property-newline: 0 */
 import "mocha";
-import { expect } from "chai";
-import { set, InsertMode } from "../../lib/set";
+import {expect} from "chai";
+import {InsertMode, set} from "../../lib/set";
 
 /*
     ??? Syntax
@@ -156,6 +156,64 @@ describe("set", () => {
             );
             expect(result).to.deep.eq({ list: [1, { value: "t" }, 3] });
         });
+
+        it("should merge into object nested in single-level array", () => {
+            const result = set(
+                [{ text: 'A' }, { text: 'B' }],
+                "#/1",
+                { additionalText: 'C' }
+            );
+            expect(result).to.deep.eq([{ text: 'A' }, { text: 'B', additionalText: 'C' } ]);
+        });
+
+        it("should replace into object nested in single-level array", () => {
+            const result = set(
+                [{ text: 'A' }, { text: 'B' }],
+                "#/1",
+                { additionalText: 'C' },
+                InsertMode.REPLACE_ITEMS
+            );
+            expect(result).to.deep.eq([{ text: 'A' }, { additionalText: 'C' } ])
+        });
+
+        it("should insert into object nested in single-level array", () => {
+            const result = set(
+                [{ text: 'A' }, { text: 'B' }],
+                "#/1",
+                { additionalText: 'C' },
+                InsertMode.INSERT_ITEMS
+            );
+            expect(result).to.deep.eq([{ text: 'A' }, { additionalText: 'C' }, { text: 'B' } ])
+        });
+
+        it("should merge into object nested in multi-level array", () => {
+            const result = set(
+                [[{ text: 'A' }, { text: 'B' } ]],
+                "#/0/1",
+                { additionalText: 'C' }
+            );
+            expect(result).to.deep.eq([[{ text: 'A' }, { text: 'B', additionalText: 'C' } ]]);
+        });
+
+        it("should replace into object nested in multi-level array", () => {
+            const result = set(
+                [[{ text: 'A' }, { text: 'B' } ]],
+                "#/0/1",
+                { additionalText: 'C' },
+                InsertMode.REPLACE_ITEMS
+            );
+            expect(result).to.deep.eq([[{ text: 'A' }, { additionalText: 'C' } ]]);
+        });
+
+        it("should insert into object nested in multi-level array", () => {
+            const result = set(
+                [[{ text: 'A' }, { text: 'B' } ]],
+                "#/0/1",
+                { additionalText: 'C' },
+                InsertMode.INSERT_ITEMS
+            );
+            expect(result).to.deep.eq([[{ text: 'A' }, { additionalText: 'C' }, { text: 'B' } ]]);
+        });
     });
 
     describe("queries", () => {