Add type linting

index.js

@@ -1,3 +1,6 @@
+// @ts-check
+/// <reference types="node" />
+
 'use strict';
 
 const slugify = require('./lib/slug').slugify;

lib/placeholders.js

@@ -1,3 +1,6 @@
+// @ts-check
+/// <reference types="node" />
+
 'use strict';
 
 const strftime = require('strftime');

lib/slug.js

@@ -1,3 +1,6 @@
+// @ts-check
+/// <reference types="node" />
+
 'use strict';
 
 const XRegExp = require('xregexp');
@@ -40,12 +43,12 @@ const SLUGIFY_TRAILING_LEADING_HYPHEN = /^-|-$/g;
  *
  * @name slugify
  * @param  {string} str - the string to create a slug of
- * @param  {string} [mode=default] - how string is slugified. Can be set to "default", "pretty" or "raw"
- * @param  {boolean} [cased=false] – whether to keep the character casing or not
+ * @param  {string} [mode] - how string is slugified. Can be set to "default", "pretty" or "raw"
+ * @param  {boolean} [cased] - whether to keep the character casing or not
  * @return {string} the slugified string
  * @see {@link https://github.com/jekyll/jekyll/blob/9278eb8fcec85b17573c6658d7d67ef6ea6ffb92/lib/jekyll/utils.rb#L177|Mimicked Jekyll Code}
  */
-const slugify = function (str, mode, cased) {
+const slugify = function (str, mode = 'default', cased = false) {
   if (!str) { return str; }
 
   mode = mode || 'default';

lib/url.js

@@ -1,3 +1,6 @@
+// @ts-check
+/// <reference types="node" />
+
 'use strict';
 
 const urlPlaceholders = require('./placeholders').urlPlaceholders;
@@ -64,18 +67,16 @@ const generateUrl = function (template, jekyllResource) {
  * @param {string} options.template - The String used as template for URL generation,
  * or example "/:path/:basename:output_ext", where
  * a placeholder is prefixed with a colon.
- * @param {string} options.:placeholders - A hash containing the placeholders which will be
+ * @param {Object<string,any>} options.placeholders - A hash containing the placeholders which will be
  * replaced when used inside the template. E.g.
  * { year: (new Date()).getFullYear() } would replace
  * the placeholder ":year" with the current year.
- * @param {string} options.permalink - If supplied, no URL will be generated from the
+ * @param {string} [options.permalink] - If supplied, no URL will be generated from the
  * template. Instead, the given permalink will be
  * used as URL.
  * @see {@link https://github.com/jekyll/jekyll/blob/cc82d442223bdaee36a2aceada64008a0106d82b/lib/jekyll/url.rb|Mimicked Jekyll Code}
  */
 function JekyllUrl (options) {
-  options = options || {};
-
   this.template = options.template;
   this.placeholders = options.placeholders;
   this.permalink = options.permalink;
@@ -92,7 +93,7 @@ function JekyllUrl (options) {
  * @throws {Error} if the relative URL contains a colon
  */
 JekyllUrl.prototype.toString = function () {
-  const sanitizedUrl = this.sanitize_url(this.generated_permalink() || this.generated_url());
+  const sanitizedUrl = this.sanitize_url(this.generated_permalink() || this.generated_url() || '');
 
   if (sanitizedUrl.includes(':')) {
     throw new Error('The URL' + sanitizedUrl + 'is invalid because it contains a colon.');
@@ -131,7 +132,7 @@ JekyllUrl.prototype.generated_url = function () {
  */
 JekyllUrl.prototype.generate_url = function (template) {
   return Object.keys(this.placeholders).reduce(
-    (result, token) => result.split(':' + token).join(this.constructor.escape_path(this.placeholders[token] || '')),
+    (result, token) => result.split(':' + token).join(JekyllUrl.escape_path(this.placeholders[token] || '')),
     template
   );
 };

package.json

@@ -15,6 +15,7 @@
     "skip:check:docs": "documentation readme index.js -s \"API Usage\" --no-markdown-toc --diff-only",
     "check:installed-check": "installed-check -i eslint",
     "check:lint": "eslint .",
+    "check:types": "tsc",
     "test:mocha": "NODE_ENV=test nyc --reporter=lcov --reporter text mocha test/**/*.spec.js",
     "test": "run-p check:* && run-p test:*",
     "build-docs": "documentation readme index.js -s \"API Usage\" --no-markdown-toc"
@@ -28,6 +29,9 @@
     "node": ">=10.0.0"
   },
   "devDependencies": {
+    "@types/chai": "^4.2.0",
+    "@types/mocha": "^5.2.7",
+    "@types/node": "^12.7.1",
     "chai": "^4.2.0",
     "coveralls": "^3.0.5",
     "dependency-check": "^4.1.0",
@@ -43,7 +47,8 @@
     "installed-check": "^3.0.0",
     "mocha": "^6.2.0",
     "npm-run-all": "^4.1.5",
-    "nyc": "^14.1.1"
+    "nyc": "^14.1.1",
+    "typescript": "^3.5.3"
   },
   "dependencies": {
     "strftime": "^0.10.0",

test/slug.spec.js

@@ -1,3 +1,8 @@
+// @ts-check
+/// <reference types="node" />
+/// <reference types="mocha" />
+/// <reference types="chai" />
+
 'use strict';
 
 const chai = require('chai');
@@ -11,6 +16,7 @@ describe('Slug', function () {
     // Tests taken from https://github.com/jekyll/jekyll/blob/70aa8a4e37cdbb935d8aacda3d6c6b598c2c91bb/test/test_utils.rb#L129
 
     it('should return undefined if passed undefined', () => {
+      // @ts-ignore
       should.not.exist(slugify());
     });
 

test/url.spec.js

@@ -1,3 +1,8 @@
+// @ts-check
+/// <reference types="node" />
+/// <reference types="mocha" />
+/// <reference types="chai" />
+
 'use strict';
 
 const chai = require('chai');
@@ -11,6 +16,7 @@ describe('Url', function () {
     // Tests taken from https://github.com/jekyll/jekyll/blob/a29498eaaebbccd415cc3b811d050137f456cd9a/test/test_url.rb
 
     it('should throw an exception if neither permalink or template is specified', () => {
+      // @ts-ignore
       should.Throw(() => new JekyllUrl({ placeholders: {} }));
     });
 

tsconfig.json

@@ -0,0 +1,27 @@
+
+{
+  "files": [
+    "index.js"
+  ],
+  "include": [
+    "lib/**/*.js",
+    "test/**/*.js"
+  ],
+  "compilerOptions": {
+    /* Basic Options */
+    "target": "ES2016",
+    "module": "commonjs",
+    "allowJs": true,
+    "resolveJsonModule": true,
+    "noEmit": true,
+    "maxNodeModuleJsDepth": 3,
+
+    /* Strict Type-Checking Options */
+    "strict": true,
+    "noImplicitAny": false,
+    "strictNullChecks": false,
+
+    /* Additional Checks */
+    "noUnusedLocals": true
+  }
+}