[**@intuiface/core**](../README.md)

***

# Function: Parameter()

> **Parameter**(`options?`): [`Function`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Function)

The `@Parameter` decorator enables you to declare an action's parameter or a trigger's parameter.

## Parameters

| Parameter | Type | Description |
| ------ | ------ | ------ |
| `options?` | [`IParameterOptions`](../interfaces/IParameterOptions.md) | options of the parameter (display name, description, ...) |

## Returns

[`Function`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Function)

## Examples

**An action with parameters:**

```ts
/**
 * Action to set the volume of the media.
 */
@Action({
    displayName: 'Set volume', // the display name of the action
    description: 'Set the volume.', // the description of the action
    validate: true // boolean for parameter validation
})
public setVolume(
    @Parameter({ // declaration of the parameter
        name: 'volume', // the name of the parameter (has to match the parameter)
        displayName: 'Volume', // the display name of the parameter
        description: 'Desired volume of the media', // the description of the parameter
        defaultValue: 1, // the default value of the parameter
        minValue: 0, // the minimum value of the parameter
        maxValue: 1, // the maximum value of the parameter
        type: Number // the type of the parameter
    })volume: number): void // the declaration of the parameter to use (same name)
{
    this.volume = volume; // the code of the action
}

```

**A trigger with parameters**

```ts
/**
 * Count changes event
 */
@Trigger({
    name: 'countChanged',
    displayName: 'Count changes'
})
public countChanged(
    @Parameter({
        name: 'count', // the name of the parameter (has to match the parameter)
        displayName: 'count', // the display name of the parameter
        description: 'New count value', // the description of the parameter
        type: Number // the type of the parameter
    }) count: number): void { } //the parameter
```

**A binding converter with parameters**

```ts
/**
 * Currency formatter converter
 */
export class CurrencyConverter
{
    @Converter({
        displayName: 'Format currency',
        description: 'Format a number using the selected currency.',
        validate: true
    })
    public static computeOutput(
        @Parameter({
            name: 'amount', // the name of the parameter (has to match the parameter)
            displayName: 'Amount', // the display name of the parameter
            description: 'Value to format', // the description of the parameter
            type: Number // the type of the parameter
        }) amount: number, // the declaration of the parameter to use (same name)
        @Parameter({
            name: 'currency', // the name of the parameter (has to match the parameter)
            displayName: 'Currency', // the display name of the parameter
            description: 'Currency code to apply', // the description of the parameter
            defaultValue: 'EUR', // the default value of the parameter
            type: String // the type of the parameter
        }) currency: string): string // the declaration of the parameter to use (same name)
    {
        return new Intl.NumberFormat('en-US', {
            style: 'currency',
            currency
        }).format(amount);
    }
}

```


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