gist.js

require('dotenv').config()

var express = require('express')
    , app = express()
    , bodyParser = require('body-parser')
    , fetch = require('node-fetch')
    , cookieParser = require('cookie-parser')
    , Promise = require('bluebird')
const {URLSearchParams} = require('url');
app.use(cookieParser())


function getToken() {
  const params = new URLSearchParams({
    'grant_type': 'client_credentials',
    'client_id': process.env.CLIENTID,
    'client_secret': process.env.CLIENTSECRET
  })
  return fetch('https://api.yelp.com/oauth2/token', {
    method:'POST',
    headers: {
      'Content-Type':'application/x-www-form-urlencoded'
    },
    body: params
  }).then(res => res.json())
}


app.get('/search', (req, res) => {
  Promise.try(() => {
    if(res.cookie.Token) {
      return res.cookie.Token
    }else {
      return getToken()
    }
  }).then((token) => {
    var search_params = new URLSearchParams({
      'term':'food',
      'location':'',
      'latitude':process.env.LATITUDE,     //using a sample location (will be replaced with user's current location)
      'longitude':process.env.LONGITUDE   //using a sample location (will be replaced with user's current location)
    })

    return fetch('https://api.yelp.com/v3/businesses/search', {
      method:'get',
      headers: {
        'Authorization': 'Bearer '+token.access_token
        //'Content-Type':'application/x-www-form-urlencoded'
      },
      body: search_params
    }).then(res => res.json())
  }).then((data) => {
    console.log(data)
  })
})

app.listen(4001)