Move Docusaurus 1 files into directory (#966)

* Move Docusaurus 1 into v1 directory

* Update Circle CI commands for new v1 dir

* Remove OC

* Fix tests

v1/lib/core/toc.js

@@ -0,0 +1,76 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+const Remarkable = require('remarkable');
+const mdToc = require('markdown-toc');
+const toSlug = require('./toSlug');
+
+const TABLE_OF_CONTENTS_TOKEN = '<AUTOGENERATED_TABLE_OF_CONTENTS>';
+
+/**
+ * Returns a table of content from the headings
+ *
+ * @return array
+ * Array of heading objects with `hashLink`, `content` and `children` fields
+ *
+ */
+function getTOC(content, headingTags = 'h2', subHeadingTags = 'h3') {
+  const tagToLevel = tag => Number(tag.slice(1));
+  const headingLevels = [].concat(headingTags).map(tagToLevel);
+  const subHeadingLevels = subHeadingTags
+    ? [].concat(subHeadingTags).map(tagToLevel)
+    : [];
+  const allowedHeadingLevels = headingLevels.concat(subHeadingLevels);
+  const md = new Remarkable();
+  const headings = mdToc(content).json;
+  const toc = [];
+  const context = {};
+  let current;
+
+  headings.forEach(heading => {
+    // we need always generate slugs to ensure, that we will have consistent
+    // slug indexes for headings with the same names
+    const hashLink = toSlug(heading.content, context);
+    if (!allowedHeadingLevels.includes(heading.lvl)) {
+      return;
+    }
+    const rawContent = mdToc.titleize(heading.content);
+    const entry = {
+      hashLink,
+      rawContent,
+      content: md.renderInline(rawContent),
+      children: [],
+    };
+    if (headingLevels.includes(heading.lvl)) {
+      toc.push(entry);
+      current = entry;
+    } else if (current) {
+      current.children.push(entry);
+    }
+  });
+  return toc;
+}
+
+// takes the content of a doc article and returns the content with a table of
+// contents inserted
+function insertTOC(rawContent) {
+  if (!rawContent || rawContent.indexOf(TABLE_OF_CONTENTS_TOKEN) === -1) {
+    return rawContent;
+  }
+  const filterRe = /^`[^`]*`/;
+  const headers = getTOC(rawContent, 'h3', null);
+  const tableOfContents = headers
+    .filter(header => filterRe.test(header.rawContent))
+    .map(header => `  - [${header.rawContent}](#${header.hashLink})`)
+    .join('\n');
+  return rawContent.replace(TABLE_OF_CONTENTS_TOKEN, tableOfContents);
+}
+
+module.exports = {
+  getTOC,
+  insertTOC,
+};