# KeywordValidator
[](https://travis-ci.org/nsweeting/keyword_validator)
[](https://hex.pm/packages/keyword_validator)
KeywordValidator provides a simple interface to validate keyword lists in Elixir.
## Installation
The package can be installed by adding `keyword_validator` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:keyword_validator, "~> 2.0"}
]
end
```
## Documentation
Please see [HexDocs](https://hexdocs.pm/keyword_validator) for additional documentation.
## Getting Started
To begin validating, we must first create a schema that defines the rules for our
keyword list.
A schema is a simple keyword list with each value representing the options available for validation.
If the validation passes, we are returned a valid keyword list.
```elixir
iex> keyword = [foo: :foo, bar: "one"]
iex> schema = [
foo: [is: :atom, required: true],
bar: [is: {:in, ["one", "two", "three"]}]
]
iex> KeywordValidator.validate(keyword, schema)
{:ok, [foo: :foo, bar: "one"]}
```
To avoid additional schema validation - define your schemas as module attributes.
```
@opts_schema KeywordValidator.schema!([foo: [is: :integer]])
```
If validation fails on any of the keys, a keyword list of the invalid entries and the
associated errors is returned.
```elixir
iex> keyword = [foo: "foo", bar: "bar"]
iex> schema = [
foo: [is: :atom, required: true],
bar: [is: {:in, ["one", "two", "three"]}]
]
iex> KeywordValidator.validate(keyword, schema)
{:error, [bar: ["must be one of: [\"one\", \"two\", \"three\"]"], foo: ["must be a binary"]]}
```
We can optionally use the `KeywordValidator.validate!/2` function as well - which will raise
an error that describes the invalid key entries.
```elixir
** (ArgumentError) Invalid keyword given.
Keyword:
[foo: :foo, bar: :bar]
Invalid:
bar: ["must be one of: [:one, :two, :three]"]
foo: ["must be a binary"]
```
To view all the available validation options, please check out the [relevant documentation](https://hexdocs.pm/keyword_validator/KeywordValidator.html#validate/2).
You can optionally generate documentation from your schemas.
```
@doc """
This is a function.
## Options
#{KeywordValidator.docs(@opts_schema)}
"""
def my_function(opts) do
...
end
```
