From fdbf896a04aec63b7c422309bda86f8c5663aeae Mon Sep 17 00:00:00 2001
From: MumuTW <clothl47364@gmail.com>
Date: Fri, 6 Mar 2026 05:45:13 +0000
Subject: [PATCH] Fix decimal input handling in DynamicJsonForm number fields

---
 client/src/components/DynamicJsonForm.tsx     | 66 ++++++++++++++++++-
 .../__tests__/DynamicJsonForm.test.tsx        | 25 ++++++-
 2 files changed, 88 insertions(+), 3 deletions(-)

diff --git a/client/src/components/DynamicJsonForm.tsx b/client/src/components/DynamicJsonForm.tsx
index ecd150f22..90249ab1c 100644
--- a/client/src/components/DynamicJsonForm.tsx
+++ b/client/src/components/DynamicJsonForm.tsx
@@ -125,6 +125,9 @@ const DynamicJsonForm = forwardRef<DynamicJsonFormRef, DynamicJsonFormProps>(
     const [rawJsonValue, setRawJsonValue] = useState<string>(
       JSON.stringify(value ?? generateDefaultValue(schema), null, 2),
     );
+    const [numericInputDrafts, setNumericInputDrafts] = useState<
+      Record<string, string>
+    >({});
 
     // Use a ref to manage debouncing timeouts to avoid parsing JSON
     // on every keystroke which would be inefficient and error-prone
@@ -134,6 +137,37 @@ const DynamicJsonForm = forwardRef<DynamicJsonFormRef, DynamicJsonFormProps>(
       return !!jsonError;
     };
 
+    const getPathKey = (path: string[]) =>
+      path.length === 0 ? "$root" : path.join(".");
+
+    const getNumericDisplayValue = (
+      path: string[],
+      currentValue: JsonValue,
+    ): string => {
+      const pathKey = getPathKey(path);
+      if (Object.prototype.hasOwnProperty.call(numericInputDrafts, pathKey)) {
+        return numericInputDrafts[pathKey];
+      }
+      return typeof currentValue === "number" ? currentValue.toString() : "";
+    };
+
+    const updateNumericDraft = (path: string[], draftValue: string) => {
+      const pathKey = getPathKey(path);
+      setNumericInputDrafts((prev) => ({ ...prev, [pathKey]: draftValue }));
+    };
+
+    const clearNumericDraft = (path: string[]) => {
+      const pathKey = getPathKey(path);
+      setNumericInputDrafts((prev) => {
+        if (!Object.prototype.hasOwnProperty.call(prev, pathKey)) {
+          return prev;
+        }
+        const next = { ...prev };
+        delete next[pathKey];
+        return next;
+      });
+    };
+
     // Debounce JSON parsing and parent updates to handle typing gracefully
     const debouncedUpdateParent = useCallback(
       (jsonString: string) => {
@@ -429,9 +463,10 @@ const DynamicJsonForm = forwardRef<DynamicJsonFormRef, DynamicJsonFormProps>(
           return (
             <Input
               type="number"
-              value={(currentValue as number)?.toString() ?? ""}
+              value={getNumericDisplayValue(path, currentValue)}
               onChange={(e) => {
                 const val = e.target.value;
+                updateNumericDraft(path, val);
                 if (!val && !isRequired) {
                   handleFieldChange(path, undefined);
                 } else {
@@ -441,6 +476,19 @@ const DynamicJsonForm = forwardRef<DynamicJsonFormRef, DynamicJsonFormProps>(
                   }
                 }
               }}
+              onBlur={(e) => {
+                const val = e.target.value;
+                if (!val) {
+                  clearNumericDraft(path);
+                  return;
+                }
+
+                const num = Number(val);
+                if (!isNaN(num)) {
+                  handleFieldChange(path, num);
+                }
+                clearNumericDraft(path);
+              }}
               placeholder={propSchema.description}
               required={isRequired}
               min={propSchema.minimum}
@@ -453,9 +501,10 @@ const DynamicJsonForm = forwardRef<DynamicJsonFormRef, DynamicJsonFormProps>(
             <Input
               type="number"
               step="1"
-              value={(currentValue as number)?.toString() ?? ""}
+              value={getNumericDisplayValue(path, currentValue)}
               onChange={(e) => {
                 const val = e.target.value;
+                updateNumericDraft(path, val);
                 if (!val && !isRequired) {
                   handleFieldChange(path, undefined);
                 } else {
@@ -465,6 +514,19 @@ const DynamicJsonForm = forwardRef<DynamicJsonFormRef, DynamicJsonFormProps>(
                   }
                 }
               }}
+              onBlur={(e) => {
+                const val = e.target.value;
+                if (!val) {
+                  clearNumericDraft(path);
+                  return;
+                }
+
+                const num = Number(val);
+                if (!isNaN(num) && Number.isInteger(num)) {
+                  handleFieldChange(path, num);
+                }
+                clearNumericDraft(path);
+              }}
               placeholder={propSchema.description}
               required={isRequired}
               min={propSchema.minimum}
diff --git a/client/src/components/__tests__/DynamicJsonForm.test.tsx b/client/src/components/__tests__/DynamicJsonForm.test.tsx
index a9f17d55b..a273f75ae 100644
--- a/client/src/components/__tests__/DynamicJsonForm.test.tsx
+++ b/client/src/components/__tests__/DynamicJsonForm.test.tsx
@@ -1,7 +1,7 @@
 import { render, screen, fireEvent, waitFor } from "@testing-library/react";
 import "@testing-library/jest-dom";
 import { describe, it, expect, jest } from "@jest/globals";
-import { useRef } from "react";
+import { useRef, useState } from "react";
 import DynamicJsonForm, { DynamicJsonFormRef } from "../DynamicJsonForm";
 import type { JsonSchemaType } from "@/utils/jsonUtils";
 
@@ -402,6 +402,29 @@ describe("DynamicJsonForm Number Fields", () => {
 
       expect(onChange).toHaveBeenCalledWith(98.6);
     });
+
+    it("should preserve decimal zero while typing", () => {
+      const schema: JsonSchemaType = {
+        type: "number",
+        description: "Coordinate",
+      };
+
+      const WrappedForm = () => {
+        const [value, setValue] = useState<number>(0);
+        return (
+          <DynamicJsonForm schema={schema} value={value} onChange={setValue} />
+        );
+      };
+
+      render(<WrappedForm />);
+      const input = screen.getByRole("spinbutton") as HTMLInputElement;
+
+      fireEvent.change(input, { target: { value: "-74.0" } });
+      expect(input.value).toBe("-74.0");
+
+      fireEvent.change(input, { target: { value: "-74.01" } });
+      expect(input.value).toBe("-74.01");
+    });
   });
 });