@jupyter-widgets/base/lib/widget_style.js

// Copyright (c) Jupyter Development Team.
// Distributed under the terms of the Modified BSD License.
import { assign } from './utils';
import { WidgetModel, WidgetView } from './widget';
/**
 * Three functions to deal with some CSS attributes
 * to make them easier to use.
 */
export class StyleModel extends WidgetModel {
    defaults() {
        const Derived = this.constructor;
        return assign(super.defaults(), {
            _model_name: 'StyleModel',
            _view_name: 'StyleView',
        }, Object.keys(Derived.styleProperties).reduce((obj, key) => {
            obj[key] = Derived.styleProperties[key].default;
            return obj;
        }, {}));
    }
}
StyleModel.styleProperties = {};
export class StyleView extends WidgetView {
    /**
     * Public constructor
     */
    initialize(parameters) {
        this._traitNames = [];
        super.initialize(parameters);
        // Register the traits that live on the Python side
        const ModelType = this.model.constructor;
        for (const key of Object.keys(ModelType.styleProperties)) {
            this.registerTrait(key);
        }
        // Set the initial styles
        this.style();
    }
    /**
     * Register a CSS trait that is known by the model
     * @param trait
     */
    registerTrait(trait) {
        this._traitNames.push(trait);
        // Listen to changes, and set the value on change.
        this.listenTo(this.model, 'change:' + trait, (model, value) => {
            this.handleChange(trait, value);
        });
    }
    /**
     * Handles when a trait value changes
     */
    handleChange(trait, value) {
        // should be synchronous so that we can measure later.
        const parent = this.options.parent;
        if (parent) {
            const ModelType = this.model.constructor;
            const styleProperties = ModelType.styleProperties;
            const attribute = styleProperties[trait].attribute;
            const selector = styleProperties[trait].selector;
            const elements = selector
                ? parent.el.querySelectorAll(selector)
                : [parent.el];
            if (value === null) {
                for (let i = 0; i !== elements.length; ++i) {
                    elements[i].style.removeProperty(attribute);
                }
            }
            else {
                for (let i = 0; i !== elements.length; ++i) {
                    elements[i].style.setProperty(attribute, value);
                }
            }
        }
        else {
            console.warn('Style not applied because a parent view does not exist');
        }
    }
    /**
     * Apply styles for all registered traits
     */
    style() {
        for (const trait of this._traitNames) {
            this.handleChange(trait, this.model.get(trait));
        }
    }
    /**
     * Remove the styling from the parent view.
     */
    unstyle() {
        const parent = this.options.parent;
        const ModelType = this.model.constructor;
        const styleProperties = ModelType.styleProperties;
        this._traitNames.forEach((trait) => {
            if (parent) {
                const attribute = styleProperties[trait].attribute;
                const selector = styleProperties[trait].selector;
                const elements = selector
                    ? parent.el.querySelectorAll(selector)
                    : [parent.el];
                for (let i = 0; i !== elements.length; ++i) {
                    elements[i].style.removeProperty(attribute);
                }
            }
            else {
                console.warn('Style not removed because a parent view does not exist');
            }
        }, this);
    }
}
//# sourceMappingURL=widget_style.js.map