add ansi_to_html.d.ts. include it in build output

Author: rburns

package.json

@@ -7,7 +7,7 @@
     "node": ">=8.0.0"
   },
   "scripts": {
-    "build": "babel src --source-maps --out-dir lib",
+    "build": "babel src --source-maps --out-dir lib && cp ./src/ansi_to_html.d.ts ./lib",
     "build:watch": "babel src --source-maps --out-dir lib --watch",
     "lint": "eslint .",
     "test": "nyc mocha --reporter tap",

src/ansi_to_html.d.ts

@@ -0,0 +1,23 @@
+declare module 'ansi-to-html' {
+  interface ConverterOptions {
+    /** The default foreground color used when reset color codes are encountered. */
+    fg?: string
+    /** The default background color used when reset color codes are encountered. */
+    bg?: string
+    /** Convert newline characters to `<br/>`. */
+    newline?: boolean
+    /** Generate HTML/XML entities. */
+    escapeXML?: boolean
+    /** Save style state across invocations of `toHtml()`. */
+    stream?: boolean
+    /** Can override specific colors or the entire ANSI palette. */
+    colors?: string[] | {[code: number]: string}
+  }
+
+  class Convert {
+    constructor(options?: ConverterOptions)
+    toHtml(data: string): string
+  }
+
+  export = Convert
+}