Illustration of 2 approaches for a createUniqueCore function

unique-hypercore-creation.js

const Corestore = require("corestore")
const ram = require("random-access-memory")

async function ensureIsNonExistingCoreName (name, corestore) {
  try {
    await (corestore.get({ name, createIfMissing: false })).ready()
  } catch (e) {
    return // Error confirms it is indeed missing
  }
  throw new Error(`A hypercore with name '${name}' already exists in the corestore`)
}

async function createUniqueCore(name, corestore) {
  await ensureIsNonExistingCoreName(name, corestore)

  const core = corestore.get({ name })
  await core.ready()

  return core
}

async function createUniqueCoreComplex(name, corestore) {
  const isUniquePromise = ensureIsNonExistingCoreName(name, corestore)

  const core = corestore.get({ name })

  await isUniquePromise
  await core.ready()

  return core
}

const corestore = new Corestore(ram)
await corestore.ready()
const name = "core1"

console.log("Simple implementation (incomplete): ")
const [core1, core2] = await Promise.all(
  [createUniqueCore(name, corestore), createUniqueCore(name, corestore)]
)
console.log(core1.key, '===', core2.key) // Both are created

console.log("Complex implementation (hard to reason about): ")
await corestore.ready()
const name2 = "core3"
//Throws
const [core3, core4] = await Promise.all(
  [createUniqueCoreComplex(name2, corestore), createUniqueCoreComplex(name2, corestore)]
)