Subscriptions feature (ICreateSubscriptionRequest) does not support custom_id

[michaelkariv]

Subscriptions feature of PayPal allows sending a custom id to PayPal with the subscription.
This is important if you rely on web hooks flow.
This custom id, sent from the client to PayPal, and PayPal adds it to the subscription events message sent to the web hook end point. This allows the application server associate a payment event or subscription transaction with a specific user whose internal (custom) id the client sent.
custom id field is documented by PayPal inconsistently. It shows up on the documentation for Subscription API. However it is not mentioned in the documentation of how to use Smart Button in Subscriptions.

Though undocumented, It still works. Just add custom_id field to actions.subscription.create parameter

paypal.Buttons({
                createSubscription: function (data, actions) {
                    console.info('createSubscription:', data);
                    return actions.subscription.create({
                        'plan_id': '{{plan_id}}',
                        "custom_id": '5533062234233'
                    });
                },...

Now, the problem with ngx-paypal as of version 7.0.0 is that custom_id is not supported by the ICreateSubscriptionRequest type.

[gh-vaishnavi]

export interface myCustomIPayPalConfig extends IPayPalConfig{
createSubscription?: (data: ICreateSubscriptionCallbackData, actions: myCustomICreateSubscriptionCallbackActions) => void;
}

export interface myCustomICreateSubscriptionCallbackActions extends ICreateSubscriptionCallbackActions {
subscription: {
create: (subscription: myCustomSubscription) => Promise;
};
}

interface myCustomSubscription extends ICreateSubscriptionRequest{
custom_id?:string;
application_context?: IApplicationContext;
}