woocommerce-paypal-payments/modules.local/ppcp-onboarding/resources/js/onboarding.js

const bootstrap = () => {

    if (!typeof (PayPalCommerceGatewayOnboarding)) {
        console.error('PayPal onboarding could not be configured.');
        return;
    }

    const link = document.createElement('a');
    link.innerText = PayPalCommerceGatewayOnboarding.link.text;

    Object.entries(PayPalCommerceGatewayOnboarding.link.attributes).forEach(
        (keyValue) => {
            link.setAttribute(keyValue[0], keyValue[1]);
        }
    );

    const onboardingCallback = (authCode, sharedId) => {
        console.log(authCode);
        console.log(sharedId);
        fetch(PayPalCommerceGatewayOnboarding.endpoint, {
            method: 'POST',
            headers: {
                'content-type': 'application/json'
            },
            body: JSON.stringify({
                authCode: authCode,
                sharedId: sharedId,
                nonce: PayPalCommerceGatewayOnboarding.nonce
            })
        }).then(function(res) {
            if (!response.ok) {
                alert("Something went wrong!");
            }
        });
    }
    link.setAttribute('data-paypal-onboard-complete', onboardingCallback);

    const table = document.querySelector('.form-table');
    const wrapper = table.parentNode;
    wrapper.insertBefore(link, table);

    const script = document.createElement('script');

    Object.entries(PayPalCommerceGatewayOnboarding.script.attributes).forEach(
        (keyValue) => {
            script.setAttribute(keyValue[0], keyValue[1]);
        }
    );

    document.body.append(script);

};
bootstrap();