Anagram checker

export const take = [
  { type: "text", label: "Source text", inline: true },
  { type: "text", label: "Anagram text", inline: true },
  {
    type: "dropdown",
    label: "Compare",
    options: [
      { label: "Letters only", value: /[a-z]/ },
      { label: "Numbers and letters", value: /[a-z\d]/ },
      { label: "Everything", value: /./ },
    ],
  },
]

export const make = ([a, b, rx]) => {
  let result = []
  let message = "Your anagram doesn't match yet."
  let value = false

  const da = diff(a, b, rx)
  const db = diff(b, a, rx)

  if (da.length > 0) {
    result.push({
      type: "text",
      label: "Missing characters",
      value: da.join(" "),
      inline: true,
    })
  }

  if (db.length > 0) {
    result.push({
      type: "text",
      label: "Extra characters",
      value: db.join(" "),
      inline: true,
    })
  }

  if (da.length === 0 && db.length === 0) {
    value = true
    message = "Your anagram contains all the letters!"
  }

  return [{ type: "status", value, message }, ...result]
}

const diff = (a, b, rx) => {
  a = a.toLowerCase()
  b = b.toLowerCase()

  return a
    .split("")
    .filter((c) => {
      if (!rx.test(c)) return false

      const index = b.indexOf(c)

      if (index < 0) return true

      b = b.slice(0, index) + b.slice(index + 1)

      return false
    })
    .map((c) => (c === " " ? "Space" : c))
}