> ## Documentation Index
> Fetch the complete documentation index at: https://yumebox.gal.tf/llms.txt
> Use this file to discover all available pages before exploring further.

# Examples and troubleshooting

This page shows JavaScript overrides as needed. Each example contains expected results or failing behavior.

## Modify scalar fields

```js 修改端口.js icon="braces" lines theme={null}
function main(profile) {
  profile["mixed-port"] = 7890;
  return profile;
}
```

```js 修改端口 diff.js icon="braces" lines theme={null}
function main(profile) {
-  profile["mixed-port"] = 10801; // [!code --]
+  profile["mixed-port"] = 7890; // [!code ++]
  return profile;
}
```

## Modify according to conditions

```js 条件修改.js icon="braces" lines theme={null}
function main(profile) {
  if (profile.mode === "rule") {
    profile["log-level"] = "info";
  }
  return profile;
}
```

When `mode` is `rule`:

```yaml theme={null}
log-level: info
```

When the conditions are not met, the script returns the original object and no diff is generated.

## Add object field

```js 添加 DNS 字段.js icon="braces" lines theme={null}
function main(profile) {
  if (!profile.dns) profile.dns = {};
  profile.dns.enable = true;
  profile.dns["enhanced-mode"] = "fake-ip";
  return profile;
}
```

```yaml 添加 DNS 字段 diff.yaml icon="file-code" lines theme={null}
dns:
  enable: true # [!code ++]
  enhanced-mode: fake-ip # [!code ++]
```

## Use `deepMerge` to add rules

```js 添加规则.js icon="braces" lines theme={null}
function main(profile) {
  return deepMerge(profile, {
    "+rules": ["DOMAIN-SUFFIX,lan,DIRECT"],
    "rules+": ["DOMAIN-SUFFIX,example.com,PROXY"],
  }, true);
}
```

```yaml 添加规则 diff.yaml icon="file-code" lines theme={null}
rules:
  - DOMAIN-SUFFIX,lan,DIRECT # [!code ++]
  - DOMAIN-SUFFIX,old.example,DIRECT
  - DOMAIN-SUFFIX,example.com,PROXY # [!code ++]
  - MATCH,PROXY
```

JavaScript does not automatically move `MATCH` like YAML does. If the original list didn't put `MATCH` at the end, the script won't fix it for you.

## Replace object or array

```js 替换 DNS.js icon="braces" lines theme={null}
function main(profile) {
  return deepMerge(profile, {
    "dns!": {
      enable: true,
      "enhanced-mode": "fake-ip",
      nameserver: ["1.1.1.1"],
    },
  }, true);
}
```

```yaml 替换 DNS diff.yaml icon="file-code" lines theme={null}
dns:
  enable: false # [!code --]
  nameserver: # [!code --]
    - 223.5.5.5 # [!code --]
  enable: true # [!code ++]
  enhanced-mode: fake-ip # [!code ++]
  nameserver: # [!code ++]
    - 1.1.1.1 # [!code ++]
```

## Filter proxy

```js 过滤代理.js icon="braces" lines theme={null}
function main(profile) {
  const proxies = Array.isArray(profile.proxies) ? profile.proxies : [];
  profile.proxies = proxies.filter((item) => {
    const name = String((item && item.name) || "");
    return !name.includes("过期");
  });
  return profile;
}
```

```yaml 过滤代理 diff.yaml icon="file-code" lines theme={null}
proxies:
  - name: 香港节点
  - name: 过期节点 # [!code --]
```

If `profile.proxies` is not an array, the script uses an empty array and ends up with `proxies: []`.

## Modify naming policy group

```js 修改策略组.js icon="braces" lines theme={null}
function main(profile) {
  const groups = Array.isArray(profile["proxy-groups"])
    ? profile["proxy-groups"]
    : [];
  const proxy = groups.find((group) => group && group.name === "PROXY");
  if (proxy) proxy.proxies = ["DIRECT"];
  return profile;
}
```

```yaml 修改策略组 diff.yaml icon="file-code" lines theme={null}
proxy-groups:
  - name: PROXY
    proxies: # [!code --]
      - AUTO # [!code --]
      - DIRECT # [!code ++]
```

If `PROXY` is not found, the script will not create a new policy group and will not report an error.

## Read remote YAML

```js 远程 YAML.js icon="braces" lines theme={null}
async function main(profile) {
  const response = await fetch("http://127.0.0.1:8080/patch.yaml");
  if (!response.ok) return profile;
  return deepMerge(profile, await response.yaml(), true);
}
```

Remote return:

```yaml theme={null}
dns:
  enable: true
```

Expected diff:

```yaml 远程 YAML 结果 diff.yaml icon="file-code" lines theme={null}
dns:
  enable: false # [!code --]
  enable: true # [!code ++]
```

Network failure, HTTPS only support, corrupted YAML content, or incomplete Promise will cause the script to fail.

## Read remote JSON

```js 远程 JSON.js icon="braces" lines theme={null}
async function main(profile) {
  const response = await fetch("http://127.0.0.1:8080/config.json");
  if (!response.ok) return profile;

  const payload = await response.json();
  if (typeof payload.port === "number") {
    profile["mixed-port"] = payload.port;
  }
  return profile;
}
```

If `payload.port` is not a number, the script retains the original `mixed-port`.

## Request header and request body

```js POST 请求.js icon="braces" lines theme={null}
async function main(profile) {
  const response = await fetch("http://127.0.0.1:8080/patch", {
    method: "POST",
    headers: {
      "content-type": "application/json",
      authorization: "Bearer token",
    },
    body: {
      mode: profile.mode,
    },
  });

  if (!response.ok) return profile;
  return deepMerge(profile, await response.yaml(), true);
}
```

The object request body is converted to a JSON string before being sent.

## Logs and Exceptions

```js 记录并抛错.js icon="braces" lines theme={null}
function main(profile) {
  console.info("开始处理", profile.mode);
  if (!profile.mode) {
    throw new Error("缺少 mode");
  }
  return profile;
}
```

On failure:

* The current override writes `[exception] 脚本执行失败`.
* Subsequent overwrites will not proceed.
* Normal configuration will return script errors and file paths.
* Encrypted configuration does not expose configuration content and paths in errors or logs.

## Return error value

```js 返回数组.js icon="braces" lines theme={null}
function main(profile) {
  return profile.rules;
}
```

Expected results:

```text theme={null}
JS override result must be an object
```

```js 缺少 main.js icon="braces" lines theme={null}
const unused = 1;
```

Expected results:

```text theme={null}
JS override must define main(profile)
```

## Multiple JavaScript overrides

Files are executed in binding order, with subsequent scripts receiving the return value of the previous script:

```js 第一个脚本.js icon="braces" lines theme={null}
function main(profile) {
  profile.port = 2;
  return profile;
}
```

```js 第二个脚本.js icon="braces" lines theme={null}
function main(profile) {
  profile.port = profile.port + 3;
  return profile;
}
```

```yaml JavaScript 覆写链结果 diff.yaml icon="file-code" lines theme={null}
mixed-port: 1 # [!code --]
mixed-port: 5 # [!code ++]
```

When the second script lacks `main`, the function of the first script will not be reused, but will fail directly.