Add proper error handling and mesage

examples/dataset-frictionless/lib/dataset.js

@@ -5,7 +5,12 @@ import toArray from 'stream-to-array'
 
 
 export async function getDataset(directory) {
-  // get dataset descriptor and resources
+  try {
+
+    if (!directory) {
+      throw new Error('No directory provided.')
+    }
+
     const f11sDataset = await Dataset.load(directory)
     const descriptor = f11sDataset.descriptor
 
@@ -16,17 +21,50 @@ export async function getDataset(directory) {
       _tmp.size = resource.size
       return _tmp
     }))
-  const readme = descriptor.readme
+
+    const readme = descriptor.readme || ""
+
     const processed = await remark()
       .use(html)
       .process(readme)
 
     const readmeHtml = processed.toString()
+
+
     const dataset = {
       readme: readme,
       readmeHtml: readmeHtml,
       descriptor: descriptor,
-    resources: resources
+      resources: resources,
+      hasError: false,
+      errorMsg: ""
     }
     return dataset
+  } catch (err) {
+    console.log(err)
+    return {
+      hasError: true,
+      errorMsg: errorMessageMappings[err.message] || err.message
+    }
+  }
+}
+
+
+const errorMessageMappings = {
+  "No datapackage.json at destination.":
+    `
+    <div>
+      <p style="color:red;"><b>No datapackage.json file in the data directory!</b></p>
+      <p >You need to add a datapackage.json file describing your dataset to the root folder.</p>
+      <p>For more information, see <a style="color:blue;" href="https://specs.frictionlessdata.io/tabular-data-package/#example">the documentation</a></p>
+    </div>
+    `,
+  "No directory provided.":
+    `
+    <div>
+      <p style="color:red;"><b>No data directory found!</b></p>
+      <p >You need to provide a data directory with CSV data, datapackage.json, and optionally a ReadMe file.</p>
+      <p>For more information, see <a style="color:blue;" href="https://specs.frictionlessdata.io/tabular-data-package/#example">the documentation</a></p>
+    </div>
+  `,
 }