> For the complete documentation index, see [llms.txt](https://beyerleinf.gitbook.io/esbuild-azure-functions/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://beyerleinf.gitbook.io/esbuild-azure-functions/troubleshooting.md).

# Troubleshooting

Issues you might face when using esbuild-azure-functions and how to solve them

## `ReferenceError: [__dirname|__filename] is not defined in ES module scope`

This error stems from the fact that `__dirname` and `__filename` are not present in an ESM environment. To fix this, simply set `advancedOptions.enableDirnameShim` to `true` ([see config](/esbuild-azure-functions/configuration.md#enable-__dirname-shim))

## `Error: Dynamic require of "xyz" is not supported`

This error stems from esbuild not being able to convert CJS requires to ESM imports. This happens mostly (from what I've seen) with Node.js internals (like http, crypto and so on). To fix this issue you have the following options:

### Turn off code splitting

Then you also need to change the format to `cjs` **(not recommended because it increases the bundle size exponentially)**

{% tabs %}
{% tab title="Code" %}
{% code title="build.mjs" %}

```javascript
import { build } from 'esbuild-azure-functions';

await build({
  project: '.',
  clean: true,
  esbuildOptions: {
    splitting: false,
    format: 'cjs',
    outExtension: {},
  },
});

```

{% endcode %}
{% endtab %}

{% tab title="CLI" %}
{% code title="config.json" %}

```json
{
    "project": ".",
    "clean": true,
    "esbuildOptions": {
        "splitting": false,
        "format": "cjs",
        "outExtension": {}
    }
}
```

{% endcode %}
{% endtab %}
{% endtabs %}

### Create a custom setup

You can use [`@esbuild-plugins/esm-externals`](https://www.npmjs.com/package/@esbuild-plugins/esm-externals) with the following setup to fix this issue

{% tabs %}
{% tab title="Code" %}
{% code title="build.mjs" %}

```javascript
import { EsmExternalsPlugin } from '@esbuild-plugins/esm-externals';
import { build } from 'esbuild-azure-functions';
import repl from 'repl';

await build({
  project: '.',
  esbuildOptions: {
    plugins: [EsmExternalsPlugin({ externals: [...repl._builtinLibs] })],
  },
});

```

{% endcode %}
{% endtab %}
{% endtabs %}

If there are other modules causing issues for you, just add them to the `externals` options of `EsmExternalsPlugin`.

Sometimes, however, there are packages that want to patch `require` (like [`diagnostic-channel`](https://www.npmjs.com/package/diagnostic-channel)). In that case, you have to use [`config.enableRequireShim`](/esbuild-azure-functions/configuration.md#enable-require-shim). 

## The import order of global imports is wrong

esbuild has a known issue ([evanw/esbuild#399](https://github.com/evanw/esbuild/issues/399)) with the code splitting feature and global imports. You can either turn off code splitting ([see here](#turn-off-code-splitting)) or make sure to import global imports everywhere you need them.