index.js

require('dotenv').config()
const OBA = require('oba-api')
var fs = require("file-system")

// Setup authentication to api server
const client = new OBA({
    // ProQuest API Keys
    public: process.env.PUBLIC,
    secret: process.env.SECRET
})

// General usage:
// client.get({ENDPOINT}, {PARAMS});
// ENDPOINT = search | details | refine | schema | availability | holdings
// PARAMS = API url parameter options (see api docs for more info)

// Client returns a promise which resolves the APIs output in JSON

// Example search to the word 'rijk' sorted by title:

var allData = [];

client.get("search", {
        q: "format:books",
        refine: true,
        librarian: true
    })
    // Bron Sterre van Geest
    .then(response => JSON.parse(response).aquabrowser)
    .then(response => {
        var selectedRctx = []
        var selectedYears = []
        var years = getYears(selectedYears)
        selectedYears.forEach(function(years) {
            client
                .get("search", {
                    q: years,
                    librarian: true,
                    refine: true
                })
                .then(response => JSON.parse(response).aquabrowser)
                .then(response => {
                    var rctx = response.meta.rctx
                    selectedRctx.push(rctx)
                    if (selectedRctx.length == 11) {
                        selectedRctx.forEach(function(selectedRctx) {
                            client
                                .get("refine", {
                                    rctx: selectedRctx,
                                    count: 100
                                })
                                .then(response => JSON.parse(response).aquabrowser)
                                .then(response => {
                                    var genreFacet = getGenreFacet(response)
                                })
                        })
                    }
                })
        })
    })
    .catch(err => console.error(err))

// Voor elke 5 jaar worden de counts opgehaald vanaf 1965 t/m 2015
function getYears(selectedYears) {
    var period = 50
    for (var i = 0; i <= period; i = i + 5) {
        var year = "year:" + (1965 + i)
        selectedYears.push(year)
    }
}

// Vorm data om naar hoe ik het wil ontvangen
function getGenreFacet(data) {
    var languageId = data.meta["original-query"]
    var year = languageId.slice(6, 10)
    var facets = data.facets.facet
    facets.forEach(function(facets) {
        var facetId = facets.id
        if (facetId === "Genre") {
            var values = facets.value
            values.forEach(function(values) {
                var count = values.count
                var id = values.id
                allData.push({
                    year: year,
                    genre: id,
                    count: count
                }) // Data naar json file
                var allDataJson = JSON.stringify(allData)
                fs.writeFileSync("data.json", allDataJson, err => {
                    if (err) throw err
                })
            })
        }
    })
}