build(aio): add renderExamples processor

This processor will eventually replace the `{@example}` inline tags
because it provides a cleaner approach that also supports tabbed examples
straight out of the box.

The idea is that authors will simply add a `path` and (optionally) a `region`
attribute to `<code-example>` or `<code-pane>` elements in their docs.
This indicates to dgeni that the relevant example needs to be injected
into the content of this element.

For example, assume that there is an example file `toh-pt1/index.hml` with
a region called `title`, which looks like:

```
<h1>Tour of Heroes</h1>
```

Then the document author could get this to appear in the docs as a
standalone example:

```
<code-example path="toh-pt1" region="title"></code-example>
```

Or as part of a tabbed group:

```
<code-tabs>
  <code-pane path="toh-pt1" region="title"></code-pane>
</code-tabs>
```

If no `path` attribute is provided then the element is ignored, which
enables authors to provide inline code instead:

```
<code-example>
 Some &lt;html&gt escaped code
</code-example>
```

Also all attributes other than `path` and `region` are ignored and passed
through to the final rendered output allowing the author to provide
styling hints:

```
<code-example path="toh-pt1" region="title" linenums"15" class="important">
</code-example>
```

aio/transforms/examples-package/index.js

@@ -13,6 +13,7 @@ module.exports =
         .factory(require('./services/getExampleRegion'))
 
         .processor(require('./processors/collect-examples'))
+        .processor(require('./processors/render-examples'))
 
         .config(function(readFilesProcessor, exampleFileReader) {
           readFilesProcessor.fileReaders.push(exampleFileReader);

aio/transforms/examples-package/inline-tag-defs/example.js

@@ -13,8 +13,7 @@ var entities = require('entities');
  * {@example core/application_spec.ts -region=hello-app -title='Sample component' }
  * @kind function
  */
-module.exports = function exampleInlineTagDef(
-    parseArgString, exampleMap, createDocMessage, log, collectExamples, getExampleRegion) {
+module.exports = function exampleInlineTagDef(parseArgString, createDocMessage, getExampleRegion) {
   return {
     name: 'example',
     description:

aio/transforms/examples-package/processors/render-examples.js

@@ -0,0 +1,33 @@
+const { parseAttributes } = require('../utils');
+
+/**
+ * Search the renderedContent looking for code examples that have a path (and optionally a region) attribute.
+ * When they are found replace their content with the appropriate doc-region parsed previously from an example file.
+ */
+module.exports = function renderExamples(getExampleRegion) {
+  return {
+    $runAfter: ['docs-rendered'],
+    $runBefore: ['writing-files'],
+    $process: function(docs) {
+      docs.forEach(doc => {
+        if (doc.renderedContent) {
+          // We match either `code-example` or `code-pane` elements that have a path attribute
+          doc.renderedContent = doc.renderedContent.replace(/<(code-example|code-pane)([^>]*)>[^<]*<\/\1>/, (original, element, attributes) => {
+            const attrMap = parseAttributes(attributes);
+            if (attrMap.path) {
+              // We found a path attribute so look up the example and rebuild the HTML
+              const exampleContent = getExampleRegion(doc, attrMap.path, attrMap.region);
+              delete attrMap.path;
+              delete attrMap.region;
+              attributes = Object.keys(attrMap).map(key => ` ${key}="${attrMap[key].replace(/"/g, '&quot;')}"`).join('');
+              return `<${element}${attributes}>\n${exampleContent}\n</${element}>`;
+            }
+            // No path attribute so just ignore this one
+            return original;
+          });
+        }
+      });
+    }
+  };
+};
+

aio/transforms/examples-package/processors/render-examples.spec.js

@@ -0,0 +1,85 @@
+var testPackage = require('../../helpers/test-package');
+var Dgeni = require('dgeni');
+var path = require('path');
+
+describe('renderExamples processor', () => {
+  var injector, processor, exampleMap, regionParser, collectExamples, exampleMap;
+
+  beforeEach(function() {
+    const dgeni = new Dgeni([testPackage('examples-package', true)]);
+    injector = dgeni.configureInjector();
+
+    exampleMap = injector.get('exampleMap');
+    processor = injector.get('renderExamples');
+    collectExamples = injector.get('collectExamples');
+    exampleMap = injector.get('exampleMap');
+
+    collectExamples.exampleFolders = ['examples'];
+    exampleMap['examples'] = {
+      'test/url': { regions: {
+        '': { renderedContent: 'whole file' },
+        'region-1': { renderedContent: 'region 1 contents' }
+      } }
+    };
+  });
+
+  it('should run before the correct processor', () => {
+    expect(processor.$runBefore).toEqual(['writing-files'])
+  });
+
+  it('should run after the correct processor', () => {
+    expect(processor.$runAfter).toEqual(['docs-rendered']);
+  });
+
+  ['code-example', 'code-pane'].forEach(CODE_TAG =>
+    describe(CODE_TAG, () => {
+      it(`should ignore a <${CODE_TAG}> tags with no path attribute`, () => {
+        const docs = [
+          { renderedContent: `Some text\n<${CODE_TAG}>Some code</${CODE_TAG}>\n<${CODE_TAG} class="anti-pattern" title="Bad Code">do not do this</${CODE_TAG}>` }
+        ];
+        processor.$process(docs);
+        expect(docs[0].renderedContent).toEqual(`Some text\n<${CODE_TAG}>Some code</${CODE_TAG}>\n<${CODE_TAG} class="anti-pattern" title="Bad Code">do not do this</${CODE_TAG}>`);
+      });
+
+      it(`should replace the content of the <${CODE_TAG}> tag with the whole contents from an example file if a path is provided`, () => {
+        const docs = [
+          { renderedContent: `<${CODE_TAG} path="test/url">Some code</${CODE_TAG}>`}
+        ];
+        processor.$process(docs);
+        expect(docs[0].renderedContent).toEqual(`<${CODE_TAG}>\nwhole file\n</${CODE_TAG}>`);
+      });
+
+      it('should contain the region contents from the example file if a region is specified', () => {
+        const docs = [
+          { renderedContent: `<${CODE_TAG} path="test/url" region="region-1">Some code</${CODE_TAG}>` }
+        ];
+        processor.$process(docs);
+        expect(docs[0].renderedContent).toEqual(`<${CODE_TAG}>\nregion 1 contents\n</${CODE_TAG}>`);
+      });
+
+      it(`should replace the content of the <${CODE_TAG}> tag with the whole contents from an example file if the region is empty`, () => {
+        const docs = [
+          { renderedContent: `<${CODE_TAG} path="test/url" region="">Some code</${CODE_TAG}>` }
+        ];
+        processor.$process(docs);
+        expect(docs[0].renderedContent).toEqual(`<${CODE_TAG}>\nwhole file\n</${CODE_TAG}>`);
+      });
+
+      it('should remove the path and region attributes but leave the other attributes alone', () => {
+        const docs = [
+          { renderedContent: `<${CODE_TAG} class="special" path="test/url" linenums="15" region="region-1" id="some-id">Some code</${CODE_TAG}>` }
+        ];
+        processor.$process(docs);
+        expect(docs[0].renderedContent).toEqual(`<${CODE_TAG} class="special" linenums="15" id="some-id">\nregion 1 contents\n</${CODE_TAG}>`);
+      });
+
+      it('should cope with spaces and double quotes inside attribute values', () => {
+        const docs = [
+          { renderedContent: `<${CODE_TAG} title='a "quoted" value' path="test/url"></${CODE_TAG}>`}
+        ];
+        processor.$process(docs);
+        expect(docs[0].renderedContent).toEqual(`<${CODE_TAG} title="a &quot;quoted&quot; value">\nwhole file\n</${CODE_TAG}>`);
+      });
+    })
+  );
+});

aio/transforms/examples-package/utils.js

@@ -1,7 +1,93 @@
 module.exports = {
+  /**
+   * Transform the values of an object via a mapper function
+   * @param {Object} obj
+   * @param {Function} mapper
+   */
   mapObject(obj, mapper) {
     const mappedObj = {};
     Object.keys(obj).forEach(key => { mappedObj[key] = mapper(key, obj[key]); });
     return mappedObj;
+  },
+
+  /**
+   * Parses the attributes from a string taken from an HTML element start tag
+   * E.g. ` a="one" b="two" `
+   * @param {string} str
+   */
+  parseAttributes(str) {
+    const attrMap = {};
+    let index = 0, key, value;
+
+    skipSpace();
+
+    while(index < str.length) {
+      takeAttribute();
+      skipSpace();
+    }
+
+    function takeAttribute() {
+      const key = takeKey();
+      skipSpace();
+      if (tryEquals()) {
+        skipSpace();
+        const quote = tryQuote();
+        attrMap[key] = takeValue(quote);
+        // skip the closing quote or whitespace
+        index++;
+      } else {
+        attrMap[key] = true;
+      }
+    }
+
+
+    function skipSpace() {
+      while(index < str.length && /\s/.test(str[index])) {
+        index++;
+      }
+    }
+
+    function tryEquals() {
+      if (str[index] === '=') {
+        index++;
+        return true;
+      }
+    }
+
+    function takeKey() {
+      let startIndex = index;
+      while(index < str.length && /[^\s=]/.test(str[index])) {
+        index++;
+      }
+      return str.substring(startIndex, index);
+    }
+
+    function tryQuote() {
+      const quote = str[index];
+      if (['"', "'"].indexOf(quote) !== -1) {
+        index++;
+        return quote;
+      }
+    }
+
+    function takeValue(quote) {
+      let startIndex = index;
+
+      if (quote) {
+        while(index < str.length && str[index] !== quote) {
+          index++;
+        }
+        if (index >= str.length) {
+          throw new Error(`Unterminated quoted attribute value in \`${str}\`. Starting at ${startIndex}. Expected a ${quote} but got "end of string".`);
+        }
+      } else {
+        while(index < str.length && /\S/.test(str[index])) {
+          index++;
+        }
+      }
+      return str.substring(startIndex, index);
+    }
+
+    return attrMap;
   }
 };

aio/transforms/examples-package/utils.spec.js

@@ -0,0 +1,76 @@
+const { mapObject, parseAttributes } = require('./utils');
+
+fdescribe('utils', () => {
+  describe('mapObject', () => {
+    it('creates a new object', () => {
+      const testObj = { a: 1 };
+      const mappedObj = mapObject(testObj, (key, value) => value);
+      expect(mappedObj).toEqual(testObj);
+      expect(mappedObj).not.toBe(testObj);
+    });
+
+    it('maps the values via the mapper function', () => {
+      const testObj = { a: 1, b: 2 };
+      const mappedObj = mapObject(testObj, (key, value) => value * 2);
+      expect(mappedObj).toEqual({ a: 2, b: 4 });
+    });
+  });
+
+  describe('parseAttributes', () => {
+    it('should parse empty string', () => {
+      const attrs = parseAttributes('');
+      expect(attrs).toEqual({ });
+    });
+
+    it('should parse blank string', () => {
+      const attrs = parseAttributes('  ');
+      expect(attrs).toEqual({ });
+    });
+
+    it('should parse double quoted attributes', () => {
+      const attrs = parseAttributes('a="one" b="two"');
+      expect(attrs).toEqual({ a: 'one', b: 'two' });
+    });
+
+    it('should parse empty quoted attributes', () => {
+      const attrs = parseAttributes('a="" b="two"');
+      expect(attrs).toEqual({ a: '', b: 'two' });
+    });
+
+    it('should parse single quoted attributes', () => {
+      const attrs = parseAttributes('a=\'one\' b=\'two\'');
+      expect(attrs).toEqual({ a: 'one', b: 'two' });
+    });
+
+    it('should ignore whitespace', () => {
+      const attrs = parseAttributes('   a = "one"   b  =  "two"   ');
+      expect(attrs).toEqual({ a: 'one', b: 'two' });
+    });
+
+    it('should parse attributes with quotes within quotes', () => {
+      const attrs = parseAttributes('a=\'o"n"e\' b="t\'w\'o"');
+      expect(attrs).toEqual({ a: 'o"n"e', b: 't\'w\'o' });
+    });
+
+    it('should parse attributes with spaces in their values', () => {
+      const attrs = parseAttributes('a="one and two" b="three and four"');
+      expect(attrs).toEqual({ a: 'one and two', b: 'three and four' });
+    });
+
+    it('should parse empty attributes', () => {
+      const attrs = parseAttributes('a b="two"');
+      expect(attrs).toEqual({ a: true, b: 'two' });
+    });
+
+    it('should parse unquoted attributes', () => {
+      const attrs = parseAttributes('a=one b=two');
+      expect(attrs).toEqual({ a: 'one', b: 'two' });
+    });
+
+    it('should complain if a quoted attribute is not closed', () => {
+      expect(() => parseAttributes('a="" b="two')).toThrowError(
+        'Unterminated quoted attribute value in `a="" b="two`. Starting at 8. Expected a " but got "end of string".'
+      );
+    })
+  });
+});