provides more robust .csv handling with various delimiters

packages/builder/src/components/backend/TableNavigator/utils.js

@@ -58,7 +58,7 @@ export const parseFile = e => {
             resolveRows(rows)
           })
           .catch(() => {
-            reject("cannot parse csv.")
+            reject("cannot parse csv")
           })
       }
     })

packages/server/src/utilities/csv.ts

@@ -7,40 +7,51 @@ export async function jsonFromCsvString(csvString: string) {
     let numOfHeaders: number | undefined = undefined
     let headerMismatch = false
 
-    const castedWithEmptyValues = await csv({
-      ignoreEmpty: true,
-      delimiter: possibleDelimeters[i],
-    }).fromString(csvString)
+    try {
+      const castedWithEmptyValues = await csv({
+        ignoreEmpty: true,
+        delimiter: possibleDelimeters[i],
+      }).fromString(csvString)
 
-    // By default the csvtojson library casts empty values as empty strings. This
-    // is causing issues on conversion.  ignoreEmpty will remove the key completly
-    // if empty, so creating this empty object will ensure we return the values
-    // with the keys but empty values
-    const result = await csv({
-      ignoreEmpty: false,
-      delimiter: possibleDelimeters[i],
-    }).fromString(csvString)
-    for (const [i, r] of result.entries()) {
-      const columns = Object.keys(r)
-      if (numOfHeaders == null) {
-        numOfHeaders = columns.length
+      // By default the csvtojson library casts empty values as empty strings. This
+      // is causing issues on conversion.  ignoreEmpty will remove the key completly
+      // if empty, so creating this empty object will ensure we return the values
+      // with the keys but empty values
+      const result = await csv({
+        ignoreEmpty: false,
+        delimiter: possibleDelimeters[i],
+      }).fromString(csvString)
+      for (const [i, r] of result.entries()) {
+        // The purpose of this is to find rows that have been split
+        // into the wrong number of columns - Any valid .CSV file will have
+        // the same number of colums in each row
+        // If the number of columms in each row is different to
+        // the number of headers, this isn't the right delimiter
+        const columns = Object.keys(r)
+        if (numOfHeaders == null) {
+          numOfHeaders = columns.length
+        }
+        if (numOfHeaders === 1 || numOfHeaders !== columns.length) {
+          headerMismatch = true
+          break
+        }
+        for (const [key] of Object.entries(r).filter(
+          ([, value]) => value === ""
+        )) {
+          if (castedWithEmptyValues[i][key] === undefined) {
+            r[key] = null
+          }
+        }
       }
-      if (numOfHeaders !== columns.length) {
-        headerMismatch = true
-        break
+      if (headerMismatch) {
+        continue
+      } else {
+        return result
       }
-      for (const [key] of Object.entries(r).filter(
-        ([, value]) => value === ""
-      )) {
-        // if (castedWithEmptyValues[i][key] === undefined) {
-        //   r[key] = null
-        // }
-      }
-    }
-    if (headerMismatch) {
+    } catch (err) {
+      // Splitting on the wrong delimiter sometimes throws CSV parsing error
+      // (eg unterminated strings), which tells us we've picked the wrong delimiter
       continue
-    } else {
-      return result
     }
   }
   throw new Error("Unable to determine delimiter")