` becomes `Foo
-->` element, `bold="true"` was added to the text.
Keep in mind that the attribute will be set only if it is allowed by [schema](module_engine_model_schema-ModelSchema.md) configuration.
```typescript
editor.conversion.for( 'upcast' ).attributeToAttribute( {
view: 'src',
model: 'source'
} );
editor.conversion.for( 'upcast' ).attributeToAttribute( {
view: { key: 'src' },
model: 'source'
} );
editor.conversion.for( 'upcast' ).attributeToAttribute( {
view: { key: 'src' },
model: 'source',
converterPriority: 'normal'
} );
editor.conversion.for( 'upcast' ).attributeToAttribute( {
view: {
key: 'data-style',
value: /[\s\S]+/
},
model: 'styled'
} );
editor.conversion.for( 'upcast' ).attributeToAttribute( {
view: {
name: 'img',
key: 'class',
value: 'styled-dark'
},
model: {
key: 'styled',
value: 'dark'
}
} );
editor.conversion.for( 'upcast' ).attributeToAttribute( {
view: {
key: 'class',
value: /styled-[\S]+/
},
model: {
key: 'styled'
value: ( viewElement, conversionApi ) => {
const regexp = /styled-([\S]+)/;
const match = viewElement.getAttribute( 'class' ).match( regexp );
return match[ 1 ];
}
}
} );
```
Converting styles works a bit differently as it requires `view.styles` to be an object and by default a model attribute will be set to `true` by such a converter. You can set the model attribute to any value by providing the `value` callback that returns the desired value.
```typescript
// Default conversion of font-weight style will result in setting bold attribute to true.
editor.conversion.for( 'upcast' ).attributeToAttribute( {
view: {
styles: {
'font-weight': 'bold'
}
},
model: 'bold'
} );
// This converter will pass any style value to the `lineHeight` model attribute.
editor.conversion.for( 'upcast' ).attributeToAttribute( {
view: {
styles: {
'line-height': /[\s\S]+/
}
},
model: {
key: 'lineHeight',
value: ( viewElement, conversionApi ) => viewElement.getStyle( 'line-height' )
}
} );
```
See [`conversion.for()`](module_engine_conversion_conversion-Conversion.md#function-for) to learn how to add a converter to the conversion process.
[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-engine/src/conversion/upcasthelpers.ts#L322)
#### Parameters
* `config: object`
Conversion configuration.
Properties
* `config.converterPriority?: PriorityString`
Converter priority. Defaults to `low`.
* `config.model: string | object`
Model attribute key or an object with `key` and `value` properties, describing the model attribute. `value` property may be set as a function that takes a view element and [upcast conversion API](module_engine_conversion_upcastdispatcher-UpcastConversionApi.md) and returns the value. If `String` is given, the model attribute value will be same as view attribute value.
* `config.view: string | object`
Specifies which view attribute will be converted. If a `String` is passed, attributes with given key will be converted. If an `Object` is passed, it must have a required `key` property, specifying view attribute key, and may have an optional `value` property, specifying view attribute value and optional `name` property specifying a view element name from/on which the attribute should be converted. `value` can be given as a `String`, a `RegExp` or a function callback, that takes view attribute value as the only parameter and returns `Boolean`.
#### Returns
* `this`
### `dataToMarker( config = { config.converterPriority?, config.model?, config.view } ) → this`
View-to-model marker conversion helper.
Converts view data created by [`#markerToData()`](module_engine_conversion_downcasthelpers-DowncastHelpers.md#function-markerToData) back to a model marker.
This converter looks for specific view elements and view attributes that mark marker boundaries. See [`#markerToData()`](module_engine_conversion_downcasthelpers-DowncastHelpers.md#function-markerToData) to learn what view data is expected by this converter.
The `config.view` property is equal to the marker group name to convert.
By default, this converter creates markers with the `group:name` name convention (to match the default `markerToData` conversion).
The conversion configuration can take a function that will generate a marker name. If such function is set as the `config.model` parameter, it is passed the `name` part from the view element or attribute and it is expected to return a string with the marker name.
Basic usage:
```typescript
// Using the default conversion.
// In this case, all markers from the `comment` group will be converted.
// The conversion will look for ` Foo Foo ` element, `bold="true"` was added to the text. See [`attributeToAttribute`](#function-attributeToAttribute) for comparison.
Keep in mind that the attribute will be set only if it is allowed by [schema](module_engine_model_schema-ModelSchema.md) configuration.
```typescript
editor.conversion.for( 'upcast' ).elementToAttribute( {
view: 'strong',
model: 'bold'
} );
editor.conversion.for( 'upcast' ).elementToAttribute( {
view: 'strong',
model: 'bold',
converterPriority: 'high'
} );
editor.conversion.for( 'upcast' ).elementToAttribute( {
view: {
name: 'span',
classes: 'bold'
},
model: 'bold'
} );
editor.conversion.for( 'upcast' ).elementToAttribute( {
view: {
name: 'span',
classes: [ 'styled', 'styled-dark' ]
},
model: {
key: 'styled',
value: 'dark'
}
} );
editor.conversion.for( 'upcast' ).elementToAttribute( {
view: {
name: 'span',
styles: {
'font-size': /[\s\S]+/
}
},
model: {
key: 'fontSize',
value: ( viewElement, conversionApi ) => {
const fontSize = viewElement.getStyle( 'font-size' );
const value = fontSize.substr( 0, fontSize.length - 2 );
if ( value <= 10 ) {
return 'small';
} else if ( value > 12 ) {
return 'big';
}
return null;
}
}
} );
```
See [`conversion.for()`](module_engine_conversion_conversion-Conversion.md#function-for) to learn how to add a converter to the conversion process.
[See source](https://github.com/ckeditor/ckeditor5/blob/master/packages/ckeditor5-engine/src/conversion/upcasthelpers.ts#L186)
#### Parameters
* `config: object`
Conversion configuration.
Properties
* `config.converterPriority?: PriorityString`
Converter priority. Defaults to `low`.
* `config.model: string | object`
Model attribute key or an object with `key` and `value` properties, describing the model attribute. `value` property may be set as a function that takes a view element and [upcast conversion API](module_engine_conversion_upcastdispatcher-UpcastConversionApi.md) and returns the value. If `String` is given, the model attribute value will be set to `true`.
* `config.view: MatcherPattern`
Pattern matching all view elements which should be converted.
#### Returns
* `this`
### `elementToElement( config = { config.converterPriority?, config.model, config.view } ) → this`
View element to model element conversion helper.
This conversion results in creating a model element. For example, view ` Foo Foo Bar