From 3836c29608b5d2d2f4430fcb13cc41471d09bc8a Mon Sep 17 00:00:00 2001
From: Zack Stickles <zstickles@gmail.com>
Date: Tue, 19 May 2020 11:22:50 -0700
Subject: [PATCH] feat: created breadcrumb logic

---
 src/utils/create-breadcrumbs.js | 54 +++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 src/utils/create-breadcrumbs.js

diff --git a/src/utils/create-breadcrumbs.js b/src/utils/create-breadcrumbs.js
new file mode 100644
index 000000000..96452b129
--- /dev/null
+++ b/src/utils/create-breadcrumbs.js
@@ -0,0 +1,54 @@
+/**
+ * Create a flat array of breadcrumbs for a given relative url given the
+ * site structure (sidenav). Returns an empty array if no match found. NOTE:
+ * this function calls itself.
+ *
+ * @param {string} url - The relative path of the page needing breadcrumbs.
+ * @param {Object[]} links - An array of link objects for this level.
+ * @param {Object[]} [result] - An array of links representing breadcrumbs.
+ * @return {Object[]} An array of link objects representing breadcrumbs.
+ */
+const createBreadcrumbs = (url, links, result = []) => {
+  // if mising url or links, throw an error
+  if (!url || !links) {
+    throw new Error('createBreadcrumbs: Missing parameters');
+  }
+
+  // if url or link is in wrong format, throw an error
+  if (typeof url !== 'string' || !Array.isArray(links) || !links.length) {
+    throw new Error('createBreadcrumbs: Invalid parameters');
+  }
+
+  // check to see if any of the links at this level match the path
+  const match = links.find((link) => link.url === url);
+
+  // if we have a link, return the displayName at the end of the result
+  if (match) {
+    return [...result, { displayName: match.displayName }];
+  }
+
+  // Find all the links at this level with children
+  const linksWithChildren = links.filter(
+    (link) => link.children && link.children.length
+  );
+
+  // loop over all links that have children (possible branches)
+  return linksWithChildren.reduce((acc, link) => {
+    // get the crumbs by calling this function on the children for this link
+    const crumbs = createBreadcrumbs(url, link.children, result);
+
+    // if the crumbs are different, we found a valid match below this link
+    if (crumbs !== result) {
+      // get the details for this link without the children
+      const { url, displayName } = link;
+
+      // return the current crumbs, this link, and the crumbs found below
+      return [...acc, { url, displayName }, ...crumbs];
+    } else {
+      // otherwise, this is an invalid branch, just return the result so far
+      return acc;
+    }
+  }, result);
+};
+
+export default createBreadcrumbs;