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# ConfigLoader

> JSON configuration file loader with environment variable interpolation and dot-notation access.

[load]: /docs/server-sdks/reference/typescript/agents/configuration/config-loader/load

[search]: /docs/server-sdks/reference/typescript/agents/configuration/config-loader/search

[get]: /docs/server-sdks/reference/typescript/agents/configuration/config-loader/get

[has]: /docs/server-sdks/reference/typescript/agents/configuration/config-loader/has

[getall]: /docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-all

[getfilepath]: /docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-file-path

[loadfromobject]: /docs/server-sdks/reference/typescript/agents/configuration/config-loader/load-from-object

[set]: /docs/server-sdks/reference/typescript/agents/configuration/config-loader/set

`ConfigLoader` loads JSON configuration files and substitutes environment
variables using `${VAR|default}` syntax. It provides dot-notation access
for nested values and supports method chaining.

```typescript {3}
import { ConfigLoader } from '@signalwire/sdk';

const config = new ConfigLoader('./config.json');
const port = config.get<number>('server.port', 3000);
```

## **Constructor**

**`filePaths`** `string | string[]`

Path(s) to a JSON config file to load on construction. A single string is
loaded directly; an array is searched in order and the first existing file
is loaded (mirroring the Python SDK's ordered-search behaviour). If no file
in the array exists, the paths are recorded but no error is thrown. If
omitted, use [`load()`][load] or [`loadFromObject()`][loadfromobject] later.

---

## **Properties**

**`configPaths`** `string[]`

The ordered list of config file paths passed to the constructor or searched
during loading. Returns a defensive copy.

---

## **Methods**

#### [load](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/load)

Load configuration from a JSON file with env var interpolation.

#### [search](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/search)

Static method to find and load a config file from standard locations.

#### [get](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get)

Get a value by dot-notation path.

#### [set](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/set)

Set a value at a dot-notation path.

#### [has](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/has)

Check whether a dot-notation path exists.

#### [getAll](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-all)

Return a shallow copy of the entire configuration object.

#### [getFilePath](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-file-path)

Return the absolute path of the loaded config file.

#### [loadFromObject](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/load-from-object)

Load configuration from a plain object instead of a file.

#### [findConfigFile](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/find-config-file)

Find a config file without loading it (static).

#### [getConfig](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-config)

Return the full config (Python-compat alias for getAll).

#### [getConfigFile](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-config-file)

Return the loaded file path (Python-compat alias for getFilePath).

#### [hasConfig](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/has-config)

Check whether any configuration data is loaded.

#### [getSection](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-section)

Get a top-level section with env-var substitution.

#### [substituteVars](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/substitute-vars)

Recursively substitute \$\{VAR} references with coercion.

#### [mergeWithEnv](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/merge-with-env)

Merge config with prefixed environment variables.

#### [interpolateEnvVars](/docs/server-sdks/reference/typescript/agents/configuration/config-loader/interpolate-env-vars)

Interpolate \$\{VAR} in a raw string without coercion.

## **Example**

```typescript {4,7-8}
import { ConfigLoader } from '@signalwire/sdk';

// Load from a specific file
const config = new ConfigLoader('./config.json');
console.log('File:', config.getFilePath());

const port = config.get<number>('server.port', 3000);
const host = config.get<string>('server.host', '0.0.0.0');
console.log(`Listening on ${host}:${port}`);
```

> JSON configuration file loader with environment variable interpolation and dot-notation access.

## Docs

- [findConfigFile](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/find-config-file.md): Find a config file path without loading it (static helper).
- [get](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get.md): Retrieve a configuration value using a dot-notation path.
- [getAll](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-all.md): Return a shallow copy of the entire configuration object.
- [getConfig](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-config.md): Return a shallow copy of the entire configuration (Python-compat alias for getAll).
- [getConfigFile](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-config-file.md): Return the path of the loaded config file (Python-compat alias for getFilePath).
- [getFilePath](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-file-path.md): Return the absolute path of the loaded config file.
- [getSection](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/get-section.md): Get a configuration section with environment variables substituted.
- [has](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/has.md): Check whether a dot-notation path exists in the loaded configuration.
- [hasConfig](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/has-config.md): Check whether any configuration data is loaded (file or object).
- [interpolateEnvVars](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/interpolate-env-vars.md): Interpolate ${VAR|default} patterns in a raw string.
- [load](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/load.md): Load configuration from a JSON file with environment variable interpolation.
- [loadFromObject](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/load-from-object.md): Load configuration from a plain object instead of a file.
- [mergeWithEnv](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/merge-with-env.md): Merge configuration with prefix-matched environment variables.
- [search](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/search.md): Search for a config file in standard locations and load it if found.
- [set](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/set.md): Set a configuration value at a dot-notation path.
- [substituteVars](https://signalwire.com/docs/server-sdks/reference/typescript/agents/configuration/config-loader/substitute-vars.md): Recursively substitute environment variables in any value.