salix/modules/client/back/models/client-credit.js

module.exports = Self => {
    Self.observe('after save', async ctx => {
        const instance = ctx.instance;
        const models = Self.app.models;

        const clientConfig = await models.ClientConfig.findOne();
        const maxCreditRows = clientConfig.maxCreditRows;

        const clientCredit = await models.ClientCredit.find({
            where: {clientFk: instance.clientFk},
            order: 'created DESC',
            limit: maxCreditRows
        }, ctx.options);

        const lastCredit = clientCredit[maxCreditRows - 1];
        if (lastCredit) {
            await models.ClientCredit.destroyAll({
                clientFk: instance.clientFk,
                created: {lt: lastCredit.created}
            }, ctx.options);
        }
    });
};