How to read and write file using fs in node

function write(json) {
    const data = JSON.stringify(json)
    const year = json.date.getFullYear()
    const directory = `collected/${slugify(className)}/${year}`

    fs.mkdirSync(directory, { recursive: true })
    fs.writeFileSync(
        `${directory}/${slugify(studentName)}`, 
        data,
        { overwrite: true }
    )
}

async function readAll() {
    const classes = fs.readdirSync('classes')
    classes.forEach((class) => {
        const years = fs.readdirSync(`classes/${class}`)
        years.forEach((year) => {
            const students = fs.readdirSync(`classes/${class}/${year}`)
            students.forEach((student) => {
            	const data = fs.readFileSync(`classes/${class}/${year}/${student})
            	const json = JSON.parse(data)
            })
        })
    })
}