Directives

Directives can be added manually by the user, or via a plugin.

Calling a directive will alter the document in some form

Example: A directive that uppercases all the strings of a document

@uppercase

object = "world"
introduction = "hello"
sentence = "${object} ${introduction}"

{
  "object": "WORLD",
  "introduction": "HELLO",
  "sentence": "HELLO WORLD"
}

Loading the directive

kyoml.compile(
  ` 
    @uppercase

    key = 'value'
  `, {
    async: false,
    interpolation: true,
    directives: {
      uppercase: (node) => {
        //
        // Write your own directive
        //
        if (typeof node.value === "string") {
         return node.set(node.value.toUpperCase())
        }

        Object.keys(node.value).forEach(key => {
            const str = node.value[key];
            if (typeof str === "string") {
                node.value[key] = str.toUpperCase();
            }
        })
      }
    }
  }
)

The ‘node’ object

Each directive is called with a node object, which is a reference to the place in the document the directive was called at. The node object contains the following properties:

• root The root of the entire document
• path The path to the field as a string (e.g document.users[3].name)
• base The object that contains the prop referenced by the node
• key The key of the property on the base object
• value (computed) The value referenced by the node
• get(path) A helper method to retrieve any element on the document thanks to a string path
• set(value) A helper method used to replace the value referenced by the node

Calling the directive

At the root of a block

Calling a directive at the root of a block will pass the whole block to the directive

e.g

myBlock {
  @uppercase

  object = "world"
  introduction = "hello"
}

On a single value

Single values can be piped into a directive using the left or right handed pipe symbols (<| and |>)

e.g

myBlock {
  object = "world" |> @uppercase
  introduction = "hello"
}