This module defines a struct where all the supported keywords of the JSON schema specification are defined as keys. Text editors that can predict the struct keys will make autocompletion available when writing schemas.

Using in build

The JSV.Schema struct can be given to JSV.build/2:

schema = %JSV.Schema{type: :integer}
JSV.build(schema, options())

Because Elixir structs always contain all their defined keys, writing a schema as %JSV.Schema{type: :integer} is actually defining the following:

%JSV.Schema{
  type: :integer,
  "$id": nil
  additionalItems: nil,
  additionalProperties: nil,
  allOf: nil,
  anyOf: nil,
  contains: nil,
  # etc...
}

For that reason, when giving a JSV.Schema struct to JSV.build/2, any nil value is ignored. This is not the case with other strucs or maps.

Note that JSV.build/2 does not require JSV.Schema structs, any map with binary or atom keys is accepted.

This is also why the JSV.Schema struct does not define the const keyword, because nil is a valid value for that keyword but there is no way to know if the value was omitted or explicitly defined as nil. To circumvent that you may use the enum keyword or just use a regular map instead of this module's struct:

%JSV.Schema{enum: [nil]}
# OR
%{const: nil}

Functional helpers

This module also exports a small range of utility functions to ease writing schemas in a functional way.

This is mostly useful when generating schemas dynamically, or for shorthands.

For instance, instead of writing the following:

%Schema{
  type: :object,
  properties: %{
    name: %Schema{type: :string, description: "the name of the user"},
    age: %Schema{type: :integer, description: "the age of the user"}
  },
  required: [:name, :age]
}

One can write:

%Schema{}
|> Schema.props(
  name: Schema.string(description: "the name of the user"),
  age: Schema.integer(description: "the age of the user")
)
|> Schema.required([:name, :age])