feat(options): throw exception on undefined

Added option to throw an exception when an undefined value is
triggered

readme.md

@@ -3,7 +3,7 @@
 ![](https://img.shields.io/travis/poppinss/pope.svg)
 [![Coverage Status](https://coveralls.io/repos/poppinss/pope/badge.svg?branch=master&service=github)](https://coveralls.io/github/poppinss/pope?branch=master)
 
-Pope is a fast, minimal and micro templating engine for strings only, it plays well where you want to embed micro templates inside your module.
+Pope is a fast, minimal and micro template engine for strings only, it plays well where you want to embed micro templates inside your module.
 
 ## Examples
 
@@ -29,19 +29,40 @@ pope('There are {{0}} emails in your inbox', [20])
 
 ## Options
 
-You can also pass an options object, which takes only one param for now and that is `skipUndefined`. 
+You can also pass an options object to define the interpolation behavior.
 
-If `skipUndefined` is set to true, all unfound variables will be untouched, whereas originally they get replaced with an empty string.
+#### skipUndefined
+Do not replace the undefined values with an empty string.
 
 ```javascript
 const pope = require('pope')
 pope('There are {{0}} emails in your inbox', {}, {
  skipUndefined: true
 })
-
 // returns - There are {{0}} emails in your inbox
 ```
 
+#### throwOnUndefined
+Throw exception when a undefined value is found. `throwOnUndefined` gets priority over `skipUndefined` if both are defined.
+
+```javascript
+const pope = require('pope')
+pope('Hello {{ username }}', {}, {
+ throwOnUndefined: true
+})
+
+// throws exception
+```
+
+```js
+{ 
+ message: 'Missing value for {{ username }}',
+ key: 'username',
+ code: 'E_MISSING_KEY',
+ stack: '.....'
+}
+```
+
 
 
 ## The MIT License

src/index.js

@@ -40,7 +40,7 @@ var prop = function(obj, path) {
  * @public
  */
 var pope = function (string, data, options) {
- options = options || { skipUndefined: false }
+ options = options || { skipUndefined: false, throwOnUndefined: false }
  var regex = /\{{2}([\w\$\s]+)\}{2}/gi
  var result
  var formattedString = string
@@ -50,6 +50,11 @@ var pope = function (string, data, options) {
  var value = prop(data, item) || null
  if (value) {
  formattedString = formattedString.replace(result[0], value)
+ } else if (options.throwOnUndefined) {
+ const error = new Error('Missing value for ' + result[0])
+ error.key = item
+ error.code = 'E_MISSING_KEY'
+ throw error
  } else if (!options.skipUndefined) {
  formattedString = formattedString.replace(result[0], '')
  }

test/pope.spec.js

@@ -72,4 +72,26 @@ describe('pope', function () {
  it('skip undefined', function () {
  expect(pope("Hello {{ user_name }}", {}, { skipUndefined: true }).trim()).to.equal('Hello {{ user_name }}')
  })
+
+ it('throw exception on undefined', function () {
+ try {
+ pope("Hello {{ user_name }}", {}, { throwOnUndefined: true })
+ expect(true).to.equal(false)
+ } catch (error) {
+ expect(error.message).to.equal('Missing value for {{ user_name }}')
+ expect(error.code).to.equal('E_MISSING_KEY')
+ expect(error.key).to.equal('user_name')
+ }
+ })
+
+ it('give priority to throwOnUndefined over skipUndefined', function () {
+ try {
+ pope("Hello {{ user_name }}", {}, { throwOnUndefined: true, skipUndefined: true })
+ expect(true).to.equal(false)
+ } catch (error) {
+ expect(error.message).to.equal('Missing value for {{ user_name }}')
+ expect(error.code).to.equal('E_MISSING_KEY')
+ expect(error.key).to.equal('user_name')
+ }
+ })
 })