Write caesar cipher output from 'rotation-cipher' package to file. My decision to remove `writeCiphers` from the `rotation-cipher` package was because I wanted users to use the cipher utility on their own terms rather than forcing the package only to be used in a non-browser environment.

writeCiphers.js

async function writeCiphers(cipherObj) {
    if (!cipherObj) return
    const allCiphers = []
    const {input, folder, filename, customRotations, useAscii, randomRotations} = cipherObj;
    let uniform = makeSectionHeader(input, 'Uniform Rotations')
    let custom = makeSectionHeader(input, 'Custom Rotations', true)
    let unique = makeSectionHeader(input, 'Random Rotations', true)

    const uniformCiphers = getUniformCiphers(input, useAscii)
    uniform += uniformCiphers.join('\n')

    const customCiphers = getCustomCiphers(input, useAscii, customRotations)
    custom += customCiphers.join('\n')

    const randomCiphers = getRandomCiphers(input, useAscii, randomRotations)
    unique += randomCiphers.join('\n')

    const fileContent = `${uniform}\n${custom}\n${unique}`
    const dateString = cipherObj.date || new Date().toISOString()
    const fileExt = filename.match(/\.\w+$/gm)
    const name = filename.slice(0, -1 * fileExt[0].length)
    const pathToWrite = `${folder}/${name}-${dateString}${fileExt[0]}`

    allCiphers.push(...uniformCiphers)
    allCiphers.push(...customCiphers)
    allCiphers.push(...randomCiphers)

    fs.mkdir(folder, {recursive: true}, (err) => {
        if (err) {
            console.error(`Unable to create directory: ${err}`)
        }
        console.log(`Successfully created directory: '${folder}'`)
    })

    fs.writeFile(pathToWrite, fileContent, (err) => {
        if (err) {
            console.error(`Unable to write file: ${err}`)
        }
        console.log(`Successfully wrote file: '${pathToWrite}'`)
    })

    return {
        ciphers: allCiphers,
        fileContent: fileContent,
        createdAt: dateString,
        filePath: pathToWrite,
    }
}

And the corresponding test file for Jest. (This gist was originally apart of the package, but since it requires 'fs', places like React can't even use 'rotation-cipher')

const { writeCiphers } = require('../index')
const fs = require('fs/promises')

describe('tests for writing ciphers to output file', () => {
    beforeEach(() => {
        this.testFolder = './test-ciphers'
        this.testFile = 'test.txt'
    })

    test('write cipher to file', async () => {
        const output = await writeCiphers({
            input: 'tanner',
            folder: this.testFolder,
            filename: this.testFile,
            customRotations: [
                [15, 2, 8, 19, 12, 21],
                [3, 13, 11, 17, 10, 25],
            ],
            useAscii: false,
            randomRotations: 250,
        })

        const path = `${this.testFolder}/${this.testFile.slice(0, -4)}-${output.createdAt}.txt`
        const fileContent = await fs.readFile(path)
        
        expect(output.fileContent).toBe(fileContent.toString())
        expect(output.filePath).toBe(path)

        // delete the test folder
        await fs.rm(this.testFolder, { recursive: true })
    })
})