OWID helper

owid.ts

let global: {
    [entity: string]: {
        [year: number]: {
            [col: string]: string
        }
    }
} = {}

async function pCSV(fName: string) {
    const f: string[][] = (await Bun.file(fName + ".csv").text()).split("\n").map(l => l.split(','));
    const headings = f.shift()!
    f.forEach((l,i) => {
        let entity: string, year: string, value: string
        l.forEach((e,i) => {
            if (headings[i] == "Entity") entity = e
            if (headings[i] == "Year") year = e
            if (headings[i] == fName) value = e

            if (year == undefined || entity == undefined) return

            if (global[entity!] == undefined) global[entity!] = {}
            if (global[entity!][year!] == undefined) global[entity!][year!] = {}
            global[entity!][year!][fName] = value!
        })
    })
}

let wanted = [/*list of column headers*/]
for (let f of wanted) {
    await pCSV(f)
}
let headings = ["Entity","Year",...wanted]

let str = headings.join(',')

Object.entries(global).forEach(([country, v]) => {
    Object.entries(v).forEach(([year, v]) => {
        let workingStr: string[] = [];
        workingStr.push(country)
        workingStr.push(year)
        wanted.forEach(k => {
            workingStr.push(v[k])
        })
        str += "\n" + workingStr.join(',')
    })
})

Bun.write("output.csv", str)