metalsmith · ismay · Jan 4, 2018 · Oct 7, 2017 · Oct 7, 2017 · Oct 7, 2017
diff --git a/.babelrc b/.babelrc
@@ -1,5 +1,5 @@
 {
   "presets": [
-    ["env", { "targets": { "node": 4 } }]
+    ["env", { "targets": { "node": 6 } }]
   ]
 }
diff --git a/.eslintrc b/.eslintrc
@@ -1,12 +1,6 @@
 {
-  "extends": "airbnb-base",
+  "extends": ["airbnb-base", "prettier"],
   "env": {
     "node": true
-  },
-  "rules": {
-    "semi": 0,
-    "arrow-parens": 0,
-    "comma-dangle": 0,
-    "function-paren-newline": 0
   }
 }
diff --git a/.travis.yml b/.travis.yml
@@ -5,9 +5,8 @@ cache:
 notifications:
   email: false
 node_js:
-  - "8"
   - "6"
-  - "4"
+  - "8"
 before_install:
   - if [[ `npm -v` != 5* ]]; then npm install -g npm@5; fi
   - npm install -g greenkeeper-lockfile@1

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,141 +1,120 @@
-3.0.1 - August 2, 2017
-----------------------
+### 4.0.0 - January 4, 2018
+* breaking: dropped node 4 support
+* breaking: the filename property is no longer set automatically, use https://github.com/MoOx/metalsmith-filenames
+* removed metalsmith-engine-jstransformer for ease of maintenance
+
+### 4.0.0-alpha.2 - October 7, 2017
+* update metalsmith-engine-jstransformer to 1.0.0-alpha.2
+
+### 4.0.0-alpha.1 - October 7, 2017
+* update metalsmith-engine-jstransformer to 1.0.0-alpha.1
+
+### 3.0.1 - August 2, 2017
 * update metalsmith-engine-jstransformer to 0.1.2
 
-3.0.0 - July 26, 2017
----------------------
+### 3.0.0 - July 26, 2017
 * dropped support for iojs and node 0.12
 * allow arrays for pattern option as well
 
-2.0.1 - January 1, 2017
------------------------
+### 2.0.1 - January 1, 2017
 * correct publishing mistake
 
-2.0.0 - January 1, 2017
------------------------
+### 2.0.0 - January 1, 2017
 * abstract templating, allows user to choose which engine to use for rendering (breaking change)
 
-2.0.0-beta.1 - September 11, 2016
--------------------------------
+### 2.0.0-beta.1 - September 11, 2016
 * switch to jstransformers for rendering (breaking change)
 
-1.4.4 - May 3, 2016
--------------------
+### 1.4.4 - May 3, 2016
 * normalize partial name for windows
 
-1.4.3 - February 11, 2016
--------------------------
+### 1.4.3 - February 11, 2016
 * add rename option
 * prevent path issue on windows
 
-1.3.3 - January 27, 2016
-------------------------
+### 1.3.3 - January 27, 2016
 * update consolidate and lodash.omit
 
-1.3.2 - October 17, 2015
-------------------------
+### 1.3.2 - October 17, 2015
 * update fs-readdir-recursive
 
-1.3.1 - August 6, 2015
-----------------------
+### 1.3.1 - August 6, 2015
 * pass unrecognised `partials` options to consolidate
 
-1.3.0 - August 6, 2015
-----------------------
+### 1.3.0 - August 6, 2015
 * add swig include test
 * add error handling for unrecognised engines
 * code style, dependency and readme updates
 * add partials option and test
 
-1.2.1 - July 23, 2015
----------------------
+### 1.2.1 - July 23, 2015
 * update swig
 
-1.2.0 - July 23, 2015
----------------------
+### 1.2.0 - July 23, 2015
 * update dependencies
 * update and add badges
 
-1.1.1 - July 20, 2015
----------------------
+### 1.1.1 - July 20, 2015
 * is-utf8 should be a dependency
 * add eslint
 * add release badge
 
-1.1.0 - July 19, 2015
----------------------
+### 1.1.0 - July 19, 2015
 * update tests
 * ignore binary files
 * add travis ci and david dm badges to readme
 * add gitattributes and editorconfig to repo
 
-1.0.1 - November 22, 2014
------------------------
+### 1.0.1 - November 22, 2014
 * change name to metalsmith-in-place
 
-1.0.0 - November 18, 2014
------------------------
+### 1.0.0 - November 18, 2014
 * render files in-place by default
 * remove `default`, `directory` and `inPlace`
 
-0.6.0 - October 3, 2014
------------------------
+### 0.6.0 - October 3, 2014
 * fix to use `path` for metalsmith `1.0.0`
 
-0.5.2 - July 9, 2014
---------------------
+### 0.5.2 - July 9, 2014
 * fix breaking binary files
 
-0.5.1 - June 11, 2014
----------------------
+### 0.5.1 - June 11, 2014
 * fix race condition with stringify file contents
 
-0.5.0 - April 29, 2014
-----------------------
+### 0.5.0 - April 29, 2014
 * pass in options to consolidate.js
 
-0.4.0 - April 2, 2014
----------------------
+### 0.4.0 - April 2, 2014
 * add `default` option
 
-0.3.0 - March 10, 2014
-----------------------
+### 0.3.0 - March 10, 2014
 * add `inPlace` option
 * change `pattern` option to just filter
 
-0.2.1 - March 10, 2014
-----------------------
+### 0.2.1 - March 10, 2014
 * fix bug in matching pattern logic
 
-0.2.0 - March 8, 2014
----------------------
+### 0.2.0 - March 8, 2014
 * add rendering files in place with a `pattern`
 
-0.1.0 - March 5, 2014
----------------------
+### 0.1.0 - March 5, 2014
 * add `string` engine convenience
 
-0.0.6 - February 7, 2014
-------------------------
+### 0.0.6 - February 7, 2014
 * fix `directory` option bug
 
-0.0.5 - February 7, 2014
-------------------------
+### 0.0.5 - February 7, 2014
 * stringify `contents` on the original file data
 
-0.0.4 - February 6, 2014
-------------------------
+### 0.0.4 - February 6, 2014
 * switch to `extend` from `defaults` to avoid cloning
 * add debug statements
 
-0.0.3 - February 6, 2014
-------------------------
+### 0.0.3 - February 6, 2014
 * fix to use buffers
 
-0.0.2 - February 5, 2014
-------------------------
+### 0.0.2 - February 5, 2014
 * mix in metadata
 
-0.0.1 - February 4, 2014
-------------------------
+### 0.0.1 - February 4, 2014
 :sparkles:
diff --git a/README.md b/README.md
@@ -8,11 +8,10 @@
 
 > A metalsmith plugin for rendering templates to html
 
-This plugin allows you to render various templating languages to html. It uses
-file extensions to infer which templating engine to use. So files ending in
-`.md` will be processed as markdown, `.hbs` as handlebars, etc. You can even
-chain transformations by appending multiple extensions, which will be processed
-right-to-left.
+This plugin allows you to render various templating languages to html. It uses file extensions to
+infer which templating engine to use. So files ending in `.md` will be processed as markdown, `.hbs`
+as handlebars, etc. You can even chain transformations by appending multiple extensions, which will
+be processed right-to-left.
 
 ```
 $ npm install metalsmith-in-place
@@ -23,9 +22,9 @@ For support questions please use [stack overflow][stackoverflow-url] or our
 
 ## Example
 
-You can use `metalsmith-in-place` with metalsmith's [Javascript API](https://github.com/segmentio/metalsmith#api)
-or the [CLI](https://github.com/segmentio/metalsmith#cli). For this example
-we'll use the cli:
+You can use `metalsmith-in-place` with metalsmith's
+[Javascript API](https://github.com/segmentio/metalsmith#api) or the
+[CLI](https://github.com/segmentio/metalsmith#cli). For this example we'll use the cli:
 
 ### 1. Install metalsmith and metalsmith-in-place:
 
@@ -35,16 +34,15 @@ $ npm install --save metalsmith metalsmith-in-place
 
 ### 2. Install appropriate jstransformers
 
-Under the hood this plugin uses 
-[jstransformers](https://github.com/jstransformers/jstransformer)
-to render your html. Since there are over a 100 jstransformers we don't install
-them automatically, so you'll also need to install the appropriate
-jstransformers. 
+Under the hood this plugin uses [jstransformers](https://github.com/jstransformers/jstransformer)
+to render your html. Since there are over a 100 jstransformers we don't install them automatically,
+so you'll also need to install the appropriate jstransformers. 
 
-For example, to render markdown you would install [jstransformer-markdown](https://github.com/jstransformers/jstransformer-markdown).
-To render handlebars you would install [jstransformer-handlebars](https://github.com/jstransformers/jstransformer-handlebars).
-See the [jstransformer organisation](https://github.com/jstransformers) for all
-available jstransformers and [this dictionary](https://github.com/jstransformers/inputformat-to-jstransformer/blob/master/dictionary.json)
+For example, to render markdown you would install [jstransformer-markdown](https://github.com/jstransformers/jstransformer-markdown). To render
+handlebars you would install
+[jstransformer-handlebars](https://github.com/jstransformers/jstransformer-handlebars). See the
+[jstransformer organisation](https://github.com/jstransformers) for all available jstransformers and
+[this dictionary](https://github.com/jstransformers/inputformat-to-jstransformer/blob/master/dictionary.json)
 to see which extensions map to which jstransformer.
 
 In this case we'll use handlebars, so we'll install jstransformer-handlebars:
@@ -55,8 +53,8 @@ $ npm install --save jstransformer-handlebars
 
 ### 3. Configure metalsmith
 
-We'll create a metalsmith.json configuration file and a handlebars file for
-metalsmith-in-place to process:
+We'll create a metalsmith.json configuration file and a handlebars file for metalsmith-in-place to
+process:
 
 `./metalsmith.json`
 
@@ -99,17 +97,17 @@ Which will output the following file:
 
 ## Options
 
-* `engineOptions`: optional. Use this to pass options to the jstransformer 
-that's rendering your templates. The default is `{}`.
+* `engineOptions`: optional. Use this to pass options to the jstransformer  that's rendering your
+templates. The default is `{}`.
 
-* `pattern`: optional. By default this plugin tries to process all files. If you
-encounter problems use this option to filter. Only files that match this pattern
-will be processed. Accepts a string or an array of strings. The default is `**`.
+* `pattern`: optional. By default this plugin tries to process all files. If you encounter problems
+use this option to filter. Only files that match this pattern will be processed. Accepts a string or
+an array of strings. The default is `**`.
 
 ### `engineOptions`
 
-Use this to pass options to the jstransformer that's rendering your templates.
-So this `metalsmith.json`:
+Use this to pass options to the jstransformer that's rendering your templates. So this
+`metalsmith.json`:
 
 ```json
 {
@@ -147,33 +145,6 @@ Would only process files within the `./src/blog` folder, because the pattern is
 relative to your source folder. See [multimatch](https://github.com/sindresorhus/multimatch)
 for further details.
 
-## Options for developers of this plugin
-
-These options are only for developers of this plugin. You don't need to touch
-this for normal use, so only use this option if you know what you're doing.
-
-* `engine`: optional. Select the engine that will be used for processing files.
-The default is [metalsmith-engine-jstransformer](https://github.com/superwolff/metalsmith-engine-jstransformer),
-but any compatible engine can be used. To select a different engine you must use
-metalsmith's [Javascript API](https://github.com/segmentio/metalsmith#api) like
-so:
-
-```javascript
-var metalsmith = require('metalsmith')
-var inPlace = require('metalsmith-in-place')
-var CustomEngine = require('./custom-engine')
-
-metalsmith(__dirname)
-  .use(inPlace({
-    engine: CustomEngine
-  }))
-  .build(function(err){
-    if (err) throw err;
-  });
-```
-
-This would use the custom engine to process files.
-
 ## Credits
 
 * [Ian Storm Taylor](https://github.com/ianstormtaylor) for creating [metalsmith-templates](https://github.com/segmentio/metalsmith-templates), on which this plugin was based

diff --git a/lib/__snapshots__/index.test.js.snap b/lib/__snapshots__/index.test.js.snap
@@ -1,13 +1,5 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`metalsmith-in-place should catch errors from the engine 1`] = `"Default error from ErrorEngine"`;
+exports[`metalsmith-in-place should return an error for an invalid pattern 1`] = `"invalid pattern, the pattern option should be a string or array."`;
 
-exports[`metalsmith-in-place should throw an error for an engine with an invalid render property 1`] = `"invalid engine, the render property should be a function."`;
-
-exports[`metalsmith-in-place should throw an error for an engine without a render method 1`] = `"invalid engine, the engine instance should have a render method."`;
-
-exports[`metalsmith-in-place should throw an error for an invalid engine 1`] = `"invalid engine, the engine should be a constructor."`;
-
-exports[`metalsmith-in-place should throw an error for an invalid pattern 1`] = `"invalid pattern, the pattern option should be a string or array."`;
-
-exports[`metalsmith-in-place should throw an error for invalid options 1`] = `"invalid options, this plugin expects a single options object."`;
+exports[`metalsmith-in-place should return an error when there are no valid files to process 1`] = `"no files to process, check whether you have a jstransformer installed."`;
diff --git a/lib/get-transformer.js b/lib/get-transformer.js
@@ -0,0 +1,15 @@
+const jstransformer = require('jstransformer')
+const toTransformer = require('inputformat-to-jstransformer')
+
+const cache = {}
+
+module.exports = function getTransformer(ext) {
+  if (ext in cache) {
+    return cache[ext]
+  }
+
+  const transformer = toTransformer(ext)
+  cache[ext] = transformer ? jstransformer(transformer) : false
+
+  return cache[ext]
+}