implementation of measurement fields

src/helpers/csv.ts

@@ -1,7 +1,34 @@
 import {parseAsync} from 'json2csv';
 
-export default function csv(input: object, fields: string[], f: (err, data) => void) {
-  parseAsync(input)
+export default function csv(input: any[], f: (err, data) => void) {
+  parseAsync(input.map(e => flatten(e)))
     .then(csv => f(null, csv))
     .catch(err => f(err, null));
+}
+
+function flatten (data) {  // flatten object: {a: {b: true}} -> {a.b: true}
+  const result = {};
+  function recurse (cur, prop) {
+    if (Object(cur) !== cur || Object.keys(cur).length === 0) {
+      result[prop] = cur;
+    }
+    else if (Array.isArray(cur)) {
+      let l = 0;
+      for(let i = 0, l = cur.length; i < l; i++)
+        recurse(cur[i], prop + "[" + i + "]");
+      if (l == 0)
+        result[prop] = [];
+    }
+    else {
+      let isEmpty = true;
+      for (let p in cur) {
+        isEmpty = false;
+        recurse(cur[p], prop ? prop+"."+p : p);
+      }
+      if (isEmpty && prop)
+        result[prop] = {};
+    }
+  }
+  recurse(data, '');
+  return result;
 }