# `PhoenixKit.Utils.Values`
[🔗](https://github.com/BeamLabEU/phoenix_kit/blob/v1.7.165/lib/phoenix_kit/utils/values.ex#L1)

Small value-handling helpers used across the workspace.

# `blank_to_nil`

```elixir
@spec blank_to_nil(value) :: value | nil when value: term()
```

Returns `nil` for `nil` or blank-string inputs; passes non-blank
strings through unchanged. Useful when reading query params, form
values, or settings where empty string and `nil` should mean the
same thing.

Non-string values (e.g. a list from a `key[]=` query param) pass
through untouched — the helper only collapses the empty string, it
never raises on unexpected input.

    iex> PhoenixKit.Utils.Values.blank_to_nil(nil)
    nil
    iex> PhoenixKit.Utils.Values.blank_to_nil("")
    nil
    iex> PhoenixKit.Utils.Values.blank_to_nil("hello")
    "hello"
    iex> PhoenixKit.Utils.Values.blank_to_nil(["a", "b"])
    ["a", "b"]

# `presence`

```elixir
@spec presence(term()) :: nil | String.t()
```

Like `blank_to_nil/1`, but trims whitespace before the blank check.

Returns the trimmed string when there's content, `nil` otherwise.
Use this for inputs where leading / trailing whitespace shouldn't
count as "present" (HTML form values, URL query params that may
carry stray whitespace, scraped IDs, etc.). When the value will
already be normalised by the caller, prefer `blank_to_nil/1` to
avoid the unnecessary `String.trim/1`.

Non-string values (e.g. a list from a `key[]=` query param) yield
`nil` — the helper treats anything that isn't a non-blank string as
"not present" rather than raising on unexpected input.

    iex> PhoenixKit.Utils.Values.presence(nil)
    nil
    iex> PhoenixKit.Utils.Values.presence("   ")
    nil
    iex> PhoenixKit.Utils.Values.presence("  hello ")
    "hello"
    iex> PhoenixKit.Utils.Values.presence(["a", "b"])
    nil

---

*Consult [api-reference.md](api-reference.md) for complete listing*