Fix bug with filter function with no arguments

lib/generate-test.js

@@ -199,6 +199,20 @@ test('should generate with several filter functions', (t) => {
   t.is(ret, expected)
 })
 
+test('should generate with filter function and no arguments', (t) => {
+  const lower = (value) => value.toLowerCase()
+  const compiled = [
+    'http://example.com/',
+    {param: 'section', filters: [{function: lower}]}
+  ]
+  const params = {section: 'News'}
+  const expected = 'http://example.com/news'
+
+  const ret = generate(compiled, params)
+
+  t.is(ret, expected)
+})
+
 test('should skip filters without function', (t) => {
   const append = (value, string) => value + string
   const compiled = [

lib/generate.js

@@ -20,7 +20,8 @@ const expandParam = (params, useKeys = false, delimiter = ',') => ({
   if (filters) {
     value = filters.reduce((value, filter) => {
       if (typeof filter.function === 'function') {
-        return filter.function(value, ...filter.args)
+        const args = filter.args || []
+        return filter.function(value, ...args)
       }
       return value
     }, value)

package.json

@@ -15,9 +15,11 @@
   },
   "ava": {
     "files": [
+      "tests/**/*-test.js",
       "lib/**/*-test.js"
     ],
     "source": [
+      "index.js",
       "lib/**/!(*-test).js"
     ],
     "babel": {

tests/template-test.js

@@ -0,0 +1,47 @@
+import test from 'ava'
+
+import {compile, generate} from '..'
+
+test('should generate uri with replacement', (t) => {
+  const template = 'http://example.com/{section}{?first,max}'
+  const params = {section: 'news', first: 40, max: 20}
+  const expected = 'http://example.com/news?first=40&max=20'
+
+  const compiled = compile(template)
+  const uri = generate(compiled, params)
+
+  t.is(uri, expected)
+})
+
+test('should generate uri with optional parameters', (t) => {
+  const template = 'http://example.com/{section}{?first?,max?}'
+  const params = {section: 'news', max: 20}
+  const expected = 'http://example.com/news?max=20'
+
+  const compiled = compile(template)
+  const uri = generate(compiled, params)
+
+  t.is(uri, expected)
+})
+
+test('should generate uri with filter functions', (t) => {
+  const template = 'http://example.com/{section|append(_archive)}{?letter=name|max(1)|lower}'
+  const params = {section: 'news', name: 'John F.'}
+  const expected = 'http://example.com/news_archive?letter=j'
+
+  const compiled = compile(template)
+  const uri = generate(compiled, params)
+
+  t.is(uri, expected)
+})
+
+test('should generate empty string from empty string template', (t) => {
+  const template = ''
+  const params = {}
+  const expected = ''
+
+  const compiled = compile(template)
+  const uri = generate(compiled, params)
+
+  t.is(uri, expected)
+})