Add configTransform option

doc/options.md

@@ -30,6 +30,7 @@ authors.
 *   [options.plugins](#optionsplugins)
 *   [options.pluginPrefix](#optionspluginprefix)
 *   [options.presetPrefix](#optionspresetprefix)
+*   [options.configTransform](#optionsconfigtransform)
 *   [options.injectedPlugins](#optionsinjectedplugins)
 *   [options.color](#optionscolor)
 *   [options.silent](#optionssilent)
@@ -872,6 +873,52 @@ Where `package.json` contains:
 }
 ```
 
+## `options.configTransform`
+
+Want configuration files in a different format?  Pass a `configTransform`
+function.  It will be invoked with the parsed value from configuration
+files and should return a config object (with `presets`, `plugins`,
+`settings`, and/or `output`).
+
+*   Type: `Function`, optional.
+
+###### Example
+
+The following example processes `readme.md` and loads options from
+`custom` (from a `package.json`).  `configTransform` is invoked with
+those options and transforms it to configuration **unified-engine**
+understands.
+
+```js
+var engine = require('unified-engine');
+var remark = require('remark');
+
+engine({
+  processor: remark(),
+  globs: ['readme.md'],
+  packageField: 'custom',
+  configTransform: function (options) {
+    return {
+      output: (options || {}).generate
+    }
+  }
+}, function (err) {
+  if (err) throw err;
+});
+```
+
+Where `package.json` contains:
+
+```json
+{
+  "name": "foo",
+  "private": true,
+  "custom": {
+    "generate": true
+  }
+}
+```
+
 ## `options.injectedPlugins`
 
 Already loaded plug-ins to attach with their options to the processor

lib/configuration.js

@@ -199,9 +199,11 @@ function merge(target, configuration, settings, source, options) {
  * @param {string} filePath - File location.
  * @return {Object} - Parsed JSON.
  */
-function load(filePath, packageField) {
+function load(filePath, options) {
   var configuration = {};
   var ext = extname(filePath);
+  var packageField = options.packageField;
+  var configTransform = options.configTransform;
   var doc;
 
   try {
@@ -227,6 +229,10 @@ function load(filePath, packageField) {
     throw err;
   }
 
+  if (configTransform) {
+    configuration = configTransform(configuration);
+  }
+
   return configuration;
 }
 
@@ -257,7 +263,7 @@ function optional(config, filePath, settings) {
 }
 
 function required(config, filePath, settings, options) {
-  merge(config, load(filePath, settings.packageField), {
+  merge(config, load(filePath, settings), {
     packageField: settings.packageField,
     pluginPrefix: settings.pluginPrefix,
     presetPrefix: settings.presetPrefix,
@@ -339,8 +345,9 @@ function Configuration(settings) {
     rcPath = path.resolve(settings.cwd, rcPath);
     this.rcPath = rcPath;
 
-    /* Load it so we can fail early. */
-    load(rcPath, settings.packageField);
+    /* Load it so we can fail early (we don’t do anything with
+     * the return value though). */
+    load(rcPath, settings);
   }
 }
 
@@ -360,6 +367,7 @@ function getConfiguration(filePath, callback) {
   var configuration = self.cache[directory];
   var options = {
     rcName: settings.rcName,
+    configTransform: settings.configTransform,
     packageField: settings.packageField,
     detectConfig: settings.detectConfig,
     pluginPrefix: settings.pluginPrefix,

lib/file-set-pipeline/configure.js

@@ -25,6 +25,7 @@ function configure(context, settings) {
     detectConfig: settings.detectConfig,
     rcName: settings.rcName,
     rcPath: settings.rcPath,
+    configTransform: settings.configTransform,
     packageField: settings.packageField,
     settings: settings.settings,
     plugins: settings.plugins,

lib/index.js

@@ -112,6 +112,7 @@ function run(options, callback) {
   settings.rcPath = options.rcPath || null;
   settings.packageField = options.packageField || null;
   settings.settings = options.settings || {};
+  settings.configTransform = options.configTransform;
 
   /* Ignore. */
   detectIgnore = options.detectIgnore;

readme.md

@@ -119,6 +119,8 @@ when done.
     — When given, optional prefix to use when searching for plug-ins.
 *   [`presetPrefix`][preset-prefix] (`string`, optional)
     — When given, optional prefix to use when searching for presets.
+*   [`configTransform`][config-transform] (`Function`, optional)
+    — Transform config files from a different schema.
 *   [`injectedPlugins`][injected-plugins] (`Array`, optional)
     — List of loaded plug-ins to use.
 *   [`color`][color] (`boolean`, default: `false`)
@@ -245,6 +247,8 @@ files work.
 
 [preset-prefix]: doc/options.md#optionspresetprefix
 
+[config-transform]: doc/options.md#optionsconfigtransform
+
 [plugins]: doc/options.md#optionsplugins
 
 [injected-plugins]: doc/options.md#optionsinjectedplugins

test/configuration-transform.js

@@ -0,0 +1,89 @@
+/**
+ * @author Titus Wormer
+ * @copyright 2016 Titus Wormer
+ * @license MIT
+ * @module unified-engine
+ * @fileoverview Test suite for `unified-engine`.
+ */
+
+'use strict';
+
+/* Dependencies. */
+var path = require('path');
+var test = require('tape');
+var noop = require('./util/noop-processor');
+var spy = require('./util/spy');
+var engine = require('..');
+
+/* Methods. */
+var join = path.join;
+
+/* Constants. */
+var fixtures = join(__dirname, 'fixtures');
+
+/* Tests. */
+test('`configTransform`', function (t) {
+  t.plan(1);
+
+  t.test('should work', function (st) {
+    var stderr = spy();
+
+    st.plan(7);
+
+    engine({
+      processor: noop.use(function (processor) {
+        processor.t = st;
+      }),
+      streamError: stderr.stream,
+      cwd: join(fixtures, 'config-transform'),
+      globs: ['.'],
+      rcName: '.foorc',
+      packageField: 'foo',
+      configTransform: configTransform,
+      extensions: ['txt']
+    }, function (err, code, result) {
+      var cache = result.configuration.cache;
+      var keys = Object.keys(cache);
+
+      st.error(err, 'should not fail fatally');
+      st.equal(code, 0, 'should exit with `0`');
+      st.equal(keys.length, 1, 'should have one cache entry');
+
+      st.deepEqual(
+        cache[keys[0]].settings,
+        {
+          charlie: true,
+          bravo: true,
+          alpha: true,
+          foxtrot: true,
+          echo: true,
+          delta: true
+        },
+        'should set the correct settings'
+      );
+
+      st.deepEqual(
+        cache[keys[0]].plugins[join(fixtures, 'config-transform', 'test.js')],
+        {
+          package: ['foo', 'bar', 'baz'],
+          cascade: 5,
+          script: true,
+          nestedScript: true
+        },
+        'should pass the correct options to plugins'
+      );
+
+      st.equal(
+        stderr(),
+        'nested/one.txt: no issues found\n'
+      );
+    });
+
+    function configTransform(raw) {
+      return {
+        settings: raw.options,
+        plugins: raw.plugs
+      };
+    }
+  });
+});

test/configuration.js

@@ -103,7 +103,7 @@ test('configuration', function (t) {
 
       st.error(err, 'should not fail fatally');
       st.equal(code, 0, 'should exit with `0`');
-      st.equal(Object.keys(cache).length, 1, 'should have on cache entry');
+      st.equal(Object.keys(cache).length, 1, 'should have one cache entry');
 
       st.deepEqual(
         cache[cwd],

test/fixtures/config-transform/.foorc

@@ -0,0 +1,6 @@
+{
+  "options": {
+    "alpha": true
+  },
+  "plugs": ["./test"]
+}

test/fixtures/config-transform/.foorc.js

@@ -0,0 +1,11 @@
+module.exports = {
+  options: {
+    bravo: true
+  },
+  plugs: {
+    './test': {
+      script: true,
+      cascade: 1
+    }
+  }
+}

test/fixtures/config-transform/nested/.foorc

@@ -0,0 +1,8 @@
+{
+  "options": {
+    "delta": true
+  },
+  "plugs": [
+    "./test"
+  ]
+}

test/fixtures/config-transform/nested/.foorc.js

@@ -0,0 +1,10 @@
+module.exports.plugs = {
+  './test': {
+    nestedScript: true,
+    cascade: 5
+  }
+};
+
+module.exports.options = {
+  echo: true
+};

test/fixtures/config-transform/nested/package.json

@@ -0,0 +1,10 @@
+{
+  "foo": {
+    "options": {
+      "foxtrot": true
+    },
+    "plugs": {
+      "./test": null
+    }
+  }
+}

test/fixtures/config-transform/package.json

@@ -0,0 +1,13 @@
+{
+  "foo": {
+    "options": {
+      "charlie": true
+    },
+    "plugs": {
+      "./test": {
+        "package": ["foo", "bar", "baz"],
+        "cascade": 2
+      }
+    }
+  }
+}

test/fixtures/config-transform/test.js

@@ -0,0 +1,12 @@
+module.exports = function (processor, options) {
+  processor.t.deepEqual(
+    options,
+    {
+      script: true,
+      package: ['foo', 'bar', 'baz'],
+      nestedScript: true,
+      cascade: 5
+    },
+    'should pass the correct options to plugin `test`'
+  );
+}

test/index.js

@@ -14,6 +14,7 @@ require('./ignore');
 require('./configuration');
 require('./configuration-plugins');
 require('./configuration-presets');
+require('./configuration-transform');
 require('./stdin');
 require('./output');
 require('./tree');