salix/back/methods/vn-user/renew-token.js

const UserError = require('vn-loopback/util/user-error');

module.exports = Self => {
    Self.remoteMethodCtx('renewToken', {
        description: 'Checks if the token has more than renewPeriod seconds to live and if so, renews it',
        accessType: 'WRITE',
        accepts: [],
        returns: {
            type: 'Object',
            root: true
        },
        http: {
            path: `/renewToken`,
            verb: 'POST'
        }
    });

    Self.renewToken = async function(ctx) {
        const models = Self.app.models;
        const token = ctx.req.accessToken;

        const now = new Date();
        const differenceMilliseconds = now - token.created;
        const differenceSeconds = Math.floor(differenceMilliseconds / 1000);

        const fields = ['renewPeriod', 'courtesyTime'];
        const accessTokenConfig = await models.AccessTokenConfig.findOne({fields});

        if (differenceSeconds < accessTokenConfig.renewPeriod - accessTokenConfig.courtesyTime)
            throw new UserError(`The renew period has not been exceeded`, 'periodNotExceeded');

        await Self.logout(token.id);
        const user = await Self.findById(token.userId);
        const accessToken = await user.createAccessToken();

        return {id: accessToken.id, ttl: accessToken.ttl};
    };
};