chore: Allow non-object type items in arrays in createJsonSchema (#1104)

Author: jsantell

builder/src/utils.ts

@@ -265,24 +265,34 @@ export function createJsonSchema(
       case "object":
         if (Array.isArray(value)) {
           schema.type = "array";
-          if (value.length > 0) {
-            const properties: { [key: string]: any } = {};
-            for (let i = 0; i < value.length; i++) {
-              const item = value?.[i];
-              if (typeof item === "object" && item !== null) {
-                Object.keys(item).forEach((key) => {
-                  if (!(key in properties)) {
-                    properties[key] = analyzeType(
-                      value?.[i]?.[key],
-                    );
-                  }
-                });
+          // Check the array type. The array type is determined by the first element
+          // of the array, or if objects, a superset of all properties of the object elements.
+          // If array is empty, `items` is `{}`.
+          if (value.length === 0) {
+            schema.items = {};
+          } else {
+            const first = value[0];
+            if (first && typeof first === "object" && !Array.isArray(first)) {
+              const properties: { [key: string]: any } = {};
+              for (let i = 0; i < value.length; i++) {
+                const item = value?.[i];
+                if (typeof item === "object" && item !== null) {
+                  Object.keys(item).forEach((key) => {
+                    if (!(key in properties)) {
+                      properties[key] = analyzeType(
+                        value?.[i]?.[key],
+                      );
+                    }
+                  });
+                }
               }
+              schema.items = {
+                type: "object",
+                properties,
+              };
+            } else {
+              schema.items = analyzeType(first) as JSONSchemaMutable;
             }
-            schema.items = {
-              type: "object",
-              properties,
-            };
           }
         } else if (value !== null) {
           schema.type = "object";

builder/test/utils.test.ts

@@ -151,8 +151,7 @@ describe("createJsonSchema", () => {
     expect(arraySchema).toEqual({
       type: "array",
       items: {
-        type: "object",
-        properties: {},
+        type: "string",
       },
     });
 
@@ -195,8 +194,7 @@ describe("createJsonSchema", () => {
             array: {
               type: "array",
               items: {
-                type: "object",
-                properties: {},
+                type: "integer",
               },
             },
             value: { type: "null" },
@@ -214,6 +212,7 @@ describe("createJsonSchema", () => {
 
     expect(createJsonSchema([])).toEqual({
       type: "array",
+      items: {},
     });
   });
 
@@ -308,8 +307,7 @@ describe("createJsonSchema", () => {
     expect(schema).toEqual({
       type: "array",
       items: {
-        type: "object",
-        properties: {},
+        type: "integer",
       },
     });
   });
@@ -360,4 +358,60 @@ describe("createJsonSchema", () => {
       },
     });
   });
+
+  it("should handle multidimensional array of numbers", () => {
+    const data = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
+    expect(createJsonSchema(data)).toEqual({
+      type: "array",
+      items: {
+        type: "array",
+        items: {
+          type: "integer",
+        },
+      },
+    });
+  });
+
+  it("should handle nested array of strings", () => {
+    const data = {
+      "recipes": [{
+        "name": "Pasta Carbonara",
+        "ingredients": [
+          "200g spaghetti",
+          "100g pancetta",
+          "2 eggs",
+          "50g pecorino cheese",
+          "50g parmesan",
+          "black pepper",
+        ],
+        "instructions":
+          "Cook pasta. Fry pancetta. Mix eggs and cheese. Combine all ingredients while pasta is hot.",
+      }],
+    };
+    expect(createJsonSchema(data)).toEqual({
+      "type": "object",
+      "properties": {
+        "recipes": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "properties": {
+              "name": {
+                "type": "string",
+              },
+              "ingredients": {
+                "type": "array",
+                "items": {
+                  "type": "string",
+                },
+              },
+              "instructions": {
+                "type": "string",
+              },
+            },
+          },
+        },
+      },
+    });
+  });
 });