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

const UserError = require('vn-loopback/util/user-error');
const {models} = require('vn-loopback/server/server');

const handlePromiseLogout = (Self, {id}, courtesyTime) => {
    new Promise(res => {
        setTimeout(() => {
            res(Self.logout(id));
        }
        , courtesyTime * 1000);
    });
};
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 {accessToken: token} = ctx.req;

        // Check if current token is valid
        const isValid = await validateToken(token);
        if (isValid)
            return token;

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

        // Schedule to remove current token
        handlePromiseLogout(Self, token, courtesyTime);

        // Create new accessToken
        const user = await Self.findById(token.userId);
        const accessToken = await user.createAccessToken();

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

    async function validateToken(token) {
        const accessTokenConfig = await models.AccessTokenConfig.findOne({fields: ['renewPeriod', 'courtesyTime']});
        const now = Date.now();
        const differenceMilliseconds = now - token.created;
        const differenceSeconds = Math.floor(differenceMilliseconds / 1000);
        const isValid = differenceSeconds < accessTokenConfig.renewPeriod - accessTokenConfig.courtesyTime;

        return isValid;
    }
};