fix/table-parse-optional-chaining (#697)

* Testing additional conditional checks.

* Further checks

* Migrating to optional chaining to cleanup syntax

* Integrating Optional Chaining into Markdown:
- Added babel parser + eslint inclusion of proposed optional chaining
- Moving table parsing pluging to use optional chaining

packages/markdown/.babelrc

@@ -10,5 +10,9 @@
     ],
     "@babel/preset-react"
   ],
-  "plugins": ["@babel/plugin-proposal-class-properties", "@babel/plugin-proposal-object-rest-spread"]
+  "plugins": [
+    "@babel/plugin-proposal-class-properties",
+    "@babel/plugin-proposal-object-rest-spread",
+    "@babel/plugin-proposal-optional-chaining"
+  ]
 }

packages/markdown/.eslintrc

@@ -3,5 +3,6 @@
     "@readme/eslint-config",
     "@readme/eslint-config/react"
   ],
+  "parser": "babel-eslint",
   "root": true
 }

packages/markdown/package.json

@@ -50,6 +50,7 @@
   "license": "ISC",
   "repository": "https://github.com/readmeio/api-explorer/tree/master/packages/markdown",
   "devDependencies": {
+    "@babel/plugin-proposal-optional-chaining": "^7.9.0",
     "@readme/eslint-config": "^2.0.0",
     "css-loader": "^3.4.2",
     "eslint": "^6.5.0",

packages/markdown/processor/plugin/table-flattening.js

@@ -9,12 +9,11 @@ function transformer(ast) {
       // This is necessary to pullout all the relevant strings
 
       // Parse Header Values
-      const headerChildren = header.children && header.children.length ? header.children[0].children : [];
-      const headerValue = headerChildren.map(hc => (hc.children.length && hc.children[0].value) || '').join(' ');
+      const headerChildren = header?.children?.[0]?.children || [];
+      const headerValue = headerChildren.map(hc => hc?.children?.[0]?.value || '').join(' ');
       // Parse Body Values
-      const bodyChildren =
-        (body.children && body.children.map(bc => bc && bc.children).reduce((a, b) => a.concat(b), [])) || [];
-      const bodyValue = bodyChildren.map(bc => (bc.children.length && bc.children[0].value) || '').join(' ');
+      const bodyChildren = body?.children?.map(bc => bc?.children).reduce((a, b) => a.concat(b), []) || [];
+      const bodyValue = bodyChildren.map(bc => bc?.children?.[0]?.value || '').join(' ');
 
       return [
         {