diff --git a/.eslintrc.cjs b/.eslintrc.cjs
index c50873b..e59eea1 100644
--- a/.eslintrc.cjs
+++ b/.eslintrc.cjs
@@ -9,6 +9,7 @@ module.exports = {
   plugins: ["@typescript-eslint", "@stylistic/js", "react-refresh"],
   parser: "@typescript-eslint/parser",
   rules: {
+    eqeqeq: "error",
     "@typescript-eslint/no-namespace": "off",
     "@typescript-eslint/no-shadow": "error",
     "react-refresh/only-export-components": "warn",
diff --git a/src/components/editor.tsx b/src/components/editor.tsx
index fa087b4..32d3ddc 100644
--- a/src/components/editor.tsx
+++ b/src/components/editor.tsx
@@ -445,7 +445,7 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
 
     try {
       const str = clipboard.readText();
-      if (!str || str == "") {
+      if (!str || str === "") {
         return;
       }
       const curNodeData = findDataById(editor.selectedId);
@@ -477,7 +477,7 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
 
     try {
       const str = clipboard.readText();
-      if (!str || str == "") {
+      if (!str || str === "") {
         return;
       }
       const curNodeData = findDataById(editor.selectedId);
@@ -547,7 +547,7 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
     }
 
     const parentData = findParent(data)!;
-    parentData.children = parentData.children!.filter((e) => e.id != editor.selectedId);
+    parentData.children = parentData.children!.filter((e) => e.id !== editor.selectedId);
     refreshItem(parentData);
     selectNode(null);
     updateGrahp();
@@ -652,7 +652,7 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
       }
 
       subpath = subpath.replaceAll(Path.sep, "/");
-      if (subpath.indexOf(workspace.workdir) == -1) {
+      if (subpath.indexOf(workspace.workdir) === -1) {
         message.warning(t("node.subtreePathError"));
         return;
       }
@@ -741,7 +741,7 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
     });
 
     editor.graph.on("viewportchange", (data: any) => {
-      if (data.action == "translate" || data.action == "zoom") {
+      if (data.action === "translate" || data.action === "zoom") {
         editor.graphMatrix = data.matrix;
       }
     });
@@ -877,7 +877,7 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
         return;
       }
 
-      if (srcNodeId == dstNode.getID()) {
+      if (srcNodeId === dstNode.getID()) {
         console.log("drop same node");
         return;
       }
@@ -897,30 +897,30 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
       }
 
       const removeSrc = () => {
-        srcParent.children = srcParent.children!.filter((value) => value.id != srcData.id);
+        srcParent.children = srcParent.children!.filter((value) => value.id !== srcData.id);
       };
 
-      if (dragDir == "dragRight") {
+      if (dragDir === "dragRight") {
         removeSrc();
         if (!dstData.children) {
           dstData.children = [];
         }
         srcData.parent = dstData.id;
         dstData.children.push(srcData);
-      } else if (dragDir == "dragUp") {
+      } else if (dragDir === "dragUp") {
         if (!dstParent) {
           return;
         }
         removeSrc();
-        const idx = dstParent.children!.findIndex((value) => value.id == dstData.id);
+        const idx = dstParent.children!.findIndex((value) => value.id === dstData.id);
         srcData.parent = dstParent.id;
         dstParent.children!.splice(idx, 0, srcData);
-      } else if (dragDir == "dragDown") {
+      } else if (dragDir === "dragDown") {
         if (!dstParent) {
           return;
         }
         removeSrc();
-        const idx = dstParent.children!.findIndex((value) => value.id == dstData.id);
+        const idx = dstParent.children!.findIndex((value) => value.id === dstData.id);
         srcData.parent = dstParent.id;
         dstParent.children!.splice(idx + 1, 0, srcData);
       } else {
@@ -1248,7 +1248,7 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
                 type="text"
                 size="small"
                 style={{ width: "30px" }}
-                disabled={filterOption.results.length == 0}
+                disabled={filterOption.results.length === 0}
                 onClick={nextResult}
               />
             )}
@@ -1258,7 +1258,7 @@ export const Editor: FC<EditorProps> = ({ onUpdate: updateState, data: editor, .
                 type="text"
                 size="small"
                 style={{ width: "30px" }}
-                disabled={filterOption.results.length == 0}
+                disabled={filterOption.results.length === 0}
                 onClick={prevResult}
               />
             )}
diff --git a/src/components/inspector.tsx b/src/components/inspector.tsx
index 59e0233..a36bdf7 100644
--- a/src/components/inspector.tsx
+++ b/src/components/inspector.tsx
@@ -109,9 +109,11 @@ const NodeInspector: FC = () => {
     }
     def.args?.forEach((v) => {
       if (v.type === "json" || v.type === "json?") {
+        const value = data.args?.[v.name];
+        console.log("nameJson", v.name, value, data.args);
         form.setFieldValue(
           `args.${v.name}`,
-          JSON.stringify(data.args?.[v.name] ?? v.default, null, 2)
+          value === null ? "null" : JSON.stringify(value ?? v.default, null, 2)
         );
       } else {
         form.setFieldValue(`args.${v.name}`, data.args?.[v.name] ?? v.default);
@@ -194,7 +196,7 @@ const NodeInspector: FC = () => {
         if (v !== null && v !== undefined && v !== "") {
           data.args ||= {};
           if (arg.type === "json" || arg.type === "json?") {
-            data.args[arg.name] = JSON.parse(v);
+            data.args[arg.name] = v === "null" ? null : JSON.parse(v);
           } else {
             data.args[arg.name] = v;
           }
@@ -324,7 +326,7 @@ const NodeInspector: FC = () => {
                 <h4>{t("node.inputVariable")}</h4>
               </Divider>
               {def.input.map((v, i) => {
-                const required = v.indexOf("?") == -1;
+                const required = v.indexOf("?") === -1;
                 const desc = v.replace("?", "");
                 return (
                   <Form.Item
@@ -386,7 +388,7 @@ const NodeInspector: FC = () => {
                 <h4>{t("node.args")}</h4>
               </Divider>
               {def.args.map((v) => {
-                const required = v.type.indexOf("?") == -1;
+                const required = v.type.indexOf("?") === -1;
                 const type = v.type.replace("?", "") as NodeArgType;
                 return (
                   <Form.Item
@@ -399,9 +401,11 @@ const NodeInspector: FC = () => {
                       { required, message: t("node.fileRequired", { field: v.desc }) },
                       ({ getFieldValue, setFieldValue, isFieldValidating, validateFields }) => ({
                         validator(_, value) {
-                          if (value && (v.type == "json" || v.type == "json?")) {
+                          if (value && (v.type === "json" || v.type === "json?")) {
                             try {
-                              JSON.parse(value);
+                              if (value !== "null") {
+                                JSON.parse(value);
+                              }
                             } catch (e) {
                               return Promise.reject(new Error(t("node.invalidValue")));
                             }
@@ -474,7 +478,7 @@ const NodeInspector: FC = () => {
                 <h4>{t("node.outputVariable")}</h4>
               </Divider>
               {def.output.map((v, i) => {
-                const required = v.indexOf("?") == -1;
+                const required = v.indexOf("?") === -1;
                 const desc = v.replace("?", "");
                 return (
                   <Form.Item
@@ -580,7 +584,7 @@ const NodeDefInspector: FC = () => {
                 <h4>{t("node.inputVariable")}</h4>
               </Divider>
               {def.input.map((v, i) => {
-                const required = v.indexOf("?") == -1;
+                const required = v.indexOf("?") === -1;
                 return (
                   <Form.Item
                     label={`[${i}]`}
@@ -600,7 +604,7 @@ const NodeDefInspector: FC = () => {
                 <h4>{t("node.args")}</h4>
               </Divider>
               {def.args.map((v, i) => {
-                const required = v.type.indexOf("?") == -1;
+                const required = v.type.indexOf("?") === -1;
                 return (
                   <Form.Item
                     name={`args.${i}.type`}
@@ -628,7 +632,7 @@ const NodeDefInspector: FC = () => {
                 <h4>{t("node.outputVariable")}</h4>
               </Divider>
               {def.output.map((v, i) => {
-                const required = v.indexOf("?") == -1;
+                const required = v.indexOf("?") === -1;
                 return (
                   <Form.Item
                     label={`[${i}]`}
diff --git a/src/components/register-node.ts b/src/components/register-node.ts
index 68f994d..52d86a9 100644
--- a/src/components/register-node.ts
+++ b/src/components/register-node.ts
@@ -65,7 +65,7 @@ G6.registerNode(
       let color = nodeDef.color || NODE_COLORS[classify] || NODE_COLORS["Other"];
       if (
         !workspace.hasNodeDef(cfg.name as string) ||
-        (cfg.path && (!cfg.children || (cfg.children as []).length == 0)) ||
+        (cfg.path && (!cfg.children || (cfg.children as []).length === 0)) ||
         !checkTreeData(cfg as TreeGraphData)
       ) {
         classify = "Error";
diff --git a/src/components/workspace.tsx b/src/components/workspace.tsx
index cfa1a44..9da9ba5 100644
--- a/src/components/workspace.tsx
+++ b/src/components/workspace.tsx
@@ -156,7 +156,7 @@ export const Workspace: FC = () => {
           <div>
             <FaExclamationTriangle style={{ fontSize: "60px", color: "#FADB14" }} />
           </div>
-          {unsaves.length == 1 && (
+          {unsaves.length === 1 && (
             <div>{t("workspace.saveOnClose", { name: Path.basename(unsaves[0].path) })}</div>
           )}
           {unsaves.length > 1 && (
@@ -331,7 +331,7 @@ export const Workspace: FC = () => {
               </Flex>
             </Flex>
           )}
-          {workspace.editors.length == 0 && (
+          {workspace.editors.length === 0 && (
             <Flex vertical align="center" justify="center" style={{ height: "100%" }}>
               <Flex
                 vertical
diff --git a/src/misc/b3util.ts b/src/misc/b3util.ts
index 4b03032..9c460ac 100644
--- a/src/misc/b3util.ts
+++ b/src/misc/b3util.ts
@@ -126,8 +126,8 @@ const checkNodeArg = (
       }
       hasError = true;
     }
-  } else if (type == "json") {
-    const isJson = value !== undefined && value !== null && value !== "";
+  } else if (type === "json") {
+    const isJson = value !== undefined && value !== "";
     const isOptional = arg.type === "json?";
     if (!(isJson || isOptional)) {
       if (verbose) {
@@ -153,7 +153,7 @@ const checkNodeArg = (
 };
 
 export const checkOneof = (argValue: unknown, inputValue: unknown) => {
-  argValue = argValue ?? "";
+  argValue = argValue === undefined ? "" : argValue;
   inputValue = inputValue ?? "";
   return (argValue !== "" && inputValue === "") || (argValue === "" && inputValue !== "");
 };
@@ -164,7 +164,7 @@ export const checkNodeData = (data: NodeModel | null | undefined) => {
   }
   let hasError = false;
   const conf = useWorkspace.getState().getNodeDef(data.name);
-  if (conf.children !== undefined && conf.children != -1) {
+  if (conf.children !== undefined && conf.children !== -1) {
     const count = data.children?.length || 0;
     if (conf.children !== count) {
       hasError = true;
@@ -264,7 +264,7 @@ export const createNode = (data: TreeGraphData, includeChildren: boolean = true)
     node.args = {};
     for (const k in data.args) {
       const v = data.args[k];
-      if (v !== null && v !== undefined) {
+      if (v !== undefined) {
         node.args[k] = v;
       }
     }
@@ -307,10 +307,10 @@ const toStatusFlag = (data: TreeGraphData) => {
 const appendStatusFlag = (status: number, childStatus: number) => {
   const childSuccess = (childStatus >> StatusFlag.SUCCESS) & 1;
   const childFailure = (childStatus >> StatusFlag.FAILURE) & 1;
-  if (childSuccess == 0) {
+  if (childSuccess === 0) {
     status |= 1 << StatusFlag.SUCCESS_ZERO;
   }
-  if (childFailure == 0) {
+  if (childFailure === 0) {
     status |= 1 << StatusFlag.FAILURE_ZERO;
   }
   status |= childStatus;
@@ -404,7 +404,7 @@ export const calcTreeDataSize = (data: TreeGraphData) => {
 
 export const checkChildrenLimit = (data: TreeGraphData) => {
   const conf = data.def;
-  if (conf.children !== undefined && conf.children != -1) {
+  if (conf.children !== undefined && conf.children !== -1) {
     return (data.children?.length || 0) === conf.children;
   }
   return true;