[typescript] Add sections support to the gray-matter.d.ts typings

gray-matter.d.ts

@@ -16,36 +16,87 @@
 declare function matter<
  I extends matter.Input,
  O extends matter.GrayMatterOption<I, O>
->(input: I | { content: I }, options?: O): matter.GrayMatterFile<I>
+ >(input: I | { content: I }, options?: O): matter.GrayMatterFile<I>
 
 declare namespace matter {
  type Input = string | Buffer
  interface GrayMatterOption<
  I extends Input,
  O extends GrayMatterOption<I, O>
- > {
+  > {
  parser?: () => void
  eval?: boolean
  excerpt?: boolean | ((input: I, options: O) => string)
  excerpt_separator?: string
  engines?: {
  [index: string]:
-  | ((string) => object)
-  | { parse: (string) => object; stringify?: (object) => string }
+ | ((string) => object)
+ | { parse: (string) => object; stringify?: (object) => string }
  }
  language?: string
  delimiters?: string | [string, string]
+ sections?: boolean
+ section?: (section: GrayMatterSection, sections?: Array<GrayMatterSection>) => void
  }
+
+ /**
+ * Structure representing the matter section
+ */
+ interface GrayMatterSection {
+ /**
+ * Key of the section
+ */
+ key: string;
+ /**
+ * The object created by parsing section matter
+ */
+ data: { [key: string]: any }
+ /**
+ * The section string, with matter stripped.
+ */
+ content: string
+ }
+
+ /**
+ * Structure representing the result of parse or read operations
+ */
  interface GrayMatterFile<I extends Input> {
- data: object
+ /**
+ * The object created by parsing front-matter
+ */
+ data: { [key: string]: any }
+ /**
+ * The input string, with matter stripped.
+ * If sections were used, there will be in separate property
+ */
  content: string
+ /**
+ * An excerpt, if defined on the options
+ */
  excerpt?: string
+ /**
+ * The original input string (or buffer)
+ */
  orig: Buffer | I
+ /**
+ * The front-matter language that was parsed. yaml is the default
+ */
  language: string
+ /**
+ * The raw, un-parsed front-matter string
+ */
  matter: string
+ /**
+ * Stringify the file by converting file.data to a string in the given language, wrapping it in delimiters and prepending it to file.content.
+ * @param {string} `lang` front-matter language to use. Only YAML and JSON can be stringified
+ */
  stringify(lang: string): string
+ /**
+ * Sections, if defined on the options
+ */
+ sections?: Array<GrayMatterSection>
  }
- 
+
  /**
  * Stringify an object to YAML or the specified language, and
  * append it to the given string. By default, only YAML and JSON