woocommerce-paypal-payments/modules/ppcp-wc-gateway/resources/js/helper/preview-button.js

/**
 * Returns a Map with all input fields that are relevant to render the preview of the
 * given payment button.
 *
 * @param {string} apmName - Value of the custom attribute `data-ppcp-apm-name`.
 * @return {Map<string, {val:Function, el:HTMLInputElement}>}
 */
export function getButtonFormFields(apmName) {
    const inputFields = document.querySelectorAll(`[data-ppcp-apm-name="${apmName}"]`);

    return [...inputFields].reduce((fieldMap, el) => {
        const key = el.dataset.ppcpFieldName;
        let getter = () => el.value;

        if ('LABEL' === el.tagName) {
            el = el.querySelector('input[type="checkbox"]');
            getter = () => el.checked;
        }

        return fieldMap.set(key, {
            val: getter,
            el,
        });
    }, new Map());
}


/**
 * Returns a function that triggers an update of the specified preview button, when invoked.

 * @param {string} apmName
 * @return {((object) => void)}
 */
export function buttonRefreshTriggerFactory(apmName) {
    const eventName = `ppcp_paypal_render_preview_${apmName}`;

    return (settings) => {
        jQuery(document).trigger(eventName, settings);
    };
}

/**
 * Returns a function that gets the current form values of the specified preview button.
 *
 * @param {string} apmName
 * @return {() => {button: {wrapper:string, is_enabled:boolean, style:{}}}}
 */
export function buttonSettingsGetterFactory(apmName) {
    const fields = getButtonFormFields(apmName);

    return () => {
        const buttonConfig = {
            wrapper: `#ppcp${apmName}ButtonPreview`,
            'is_enabled': true,
            style: {},
        };

        fields.forEach((item, name) => {
            if ('is_enabled' === name) {
                buttonConfig[name] = item.val();
            } else {
                buttonConfig.style[name] = item.val();
            }
        });

        return { button: buttonConfig };
    };
}