dx: Add type declarations

.eslintignore

@@ -2,3 +2,4 @@
 dist/*
 coverage/*
 karma.conf.js
+/**/*.d.ts

dist/mercury.d.ts

@@ -0,0 +1,40 @@
+declare module '@postlight/parser' {
+  export type ExtractorArgs = any;
+
+  export type ParserOptions = {
+    html?: string;
+    fetchAllPages?: boolean;
+    fallback?: boolean;
+    contentType?: 'html' | 'markdown' | 'text';
+    headers?: Record<string, string>;
+    extend?: boolean;
+    customExtractor?: (args: ExtractorArgs) => ParserResult;
+  };
+
+  export type ParserResult = {
+    title: string;
+    content: string;
+    author: string;
+    date_published: string;
+    lead_image_url: string;
+    dek: string;
+    next_page_url: string;
+    url: string;
+    domain: string;
+    excerpt: string;
+    word_count: number;
+    direction: string;
+    total_pages: number;
+    rendered_pages: number;
+  };
+
+  export function parse(
+    url: string,
+    opts: ParserOptions
+  ): Promise<ParserResult>;
+
+  const exported: {
+    parse: typeof parse;
+  };
+  export default exported;
+}

rollup.config.js

@@ -1,7 +1,12 @@
 /* eslint-disable import/no-extraneous-dependencies */
+import fs from 'fs';
 import babel from 'rollup-plugin-babel';
 import commonjs from 'rollup-plugin-commonjs';
 
+const copyDeclarations = (src, dest) => {
+  fs.copyFileSync(src, dest);
+};
+
 export default {
   input: 'src/mercury.js',
   plugins: [
@@ -10,6 +15,7 @@ export default {
       externalHelpers: false,
       runtimeHelpers: true,
     }),
+    copyDeclarations('src/mercury.d.ts', 'dist/mercury.d.ts'),
   ],
   treeshake: true,
   output: {

src/mercury.d.ts

@@ -0,0 +1,40 @@
+declare module '@postlight/parser' {
+  export type ExtractorArgs = any;
+
+  export type ParserOptions = {
+    html?: string;
+    fetchAllPages?: boolean;
+    fallback?: boolean;
+    contentType?: 'html' | 'markdown' | 'text';
+    headers?: Record<string, string>;
+    extend?: boolean;
+    customExtractor?: (args: ExtractorArgs) => ParserResult;
+  };
+
+  export type ParserResult = {
+    title: string;
+    content: string;
+    author: string;
+    date_published: string;
+    lead_image_url: string;
+    dek: string;
+    next_page_url: string;
+    url: string;
+    domain: string;
+    excerpt: string;
+    word_count: number;
+    direction: string;
+    total_pages: number;
+    rendered_pages: number;
+  };
+
+  export function parse(
+    url: string,
+    opts: ParserOptions
+  ): Promise<ParserResult>;
+
+  const exported: {
+    parse: typeof parse;
+  };
+  export default exported;
+}