Set up types folder, added new tests

As discussed in PR e-mission#1061, Jiji is working on setting up a folder in
`www/js/` to contain many of our type interfaces and templates.  For
now, I've added my own `fileIOTypes.ts`.  We discussed the types added
so far, and found we were working with overlapping types! As such,
I plan to copy over her version of `DiaryTypes.ts` found in commit
ffcc871, and will use that to replace the current dataObj interface
in `controlHelper.test.ts`.

Changes made:
- Set up `www/js/types`, moved fsWindow interface there
- Added basic tests for createWriteFile

www/__tests__/controlHelper.test.ts

@@ -1,7 +1,9 @@
 import { mockLogger } from "../__mocks__/globalMocks";
 import { createWriteFile } from "../js/controlHelper";
+import { fsWindow } from "../js/types/fileIOTypes"
 
 mockLogger();
+declare let window: fsWindow;
 
 // See PR 1052 for a detailed interface
 interface dataObj {
@@ -19,22 +21,24 @@ interface dataObj {
   }
 }
 
-// These are fake values; createWriteFile does not require these objects
-// specifically, but it is better to test with similar data - using real data 
-// would take up too much code space, and we cannot use getRawEnteries() in testing
-const generateDummyValues = (arraySize: number) => {
+// createWriteFile does not require these objects specifically, but it
+// is better to test with similar data - using real data would take
+// up too much code space, and we cannot use getRawEnteries() in testing
+const generateFakeValues = (arraySize: number) => {
+  if (arraySize <= 0) 
+    return new Promise (() => {return []});
   const sampleDataObj = {
     data: {
       name: 'MODE', 
       ts: 1234567890.9876543,
-      reading: 0.1234567891011121
+      reading: 0.1234567891011121,
     },
     metadata: 'testValue #',
     user_id: {
-      $uuid: '41t0l8e00s914tval1234567u9658699'
+      $uuid: '41t0l8e00s914tval1234567u9658699',
     },
     _id: {
-      $oid: '12341x123afe3fbf541524d8'
+      $oid: '12341x123afe3fbf541524d8',
     }
   };
   // The parse/stringify lets us "deep copy" the objects, to quickly populate/change the data
@@ -43,14 +47,53 @@ const generateDummyValues = (arraySize: number) => {
     values[index].metadata = element.metadata + index.toString()
   });
 
-  return values;
+  return new Promise(() => {
+    return { phone_data: values };
+  });
 };
 
-it(`writes a file for an array of objects`, async () => {
-  const testPhoneObj = { phone_data: generateDummyValues(100) };
-  const writeFile = createWriteFile('testFile.temp');
-  const testPromise = new Promise(() => {
-    return testPhoneObj;
-  });
-  expect(testPromise.then(writeFile)).resolves.not.toThrow();
+// A variation of createShareData; confirms the file has been written,
+// without sharing the data. 
+const confirmFileExists = (fileName: string) => {
+  return function() {
+    return new Promise(function() {
+      window.requestFileSystem(window.LocalFileSystem.TEMPORARY, 0, function(fs) {
+        fs.root.getFile(fileName, null, function(fileEntry) {
+          return fileEntry.isFile;
+        });
+      });
+    });
+  };
+};
+
+it('writes a file for an array of objects', async () => {
+  const testPromiseOne = generateFakeValues(1);
+  const testPromiseTwo=  generateFakeValues(222);
+  const writeFile = createWriteFile('test_one.temp');
+
+  expect(testPromiseOne.then(writeFile)).resolves.not.toThrow();
+  expect(testPromiseTwo.then(writeFile)).resolves.not.toThrow();
 });
+
+it('correctly writes the files', async () => {
+  const fileName = 'test_two.timeline'
+  const fileExists = confirmFileExists(fileName);
+  const testPromise = generateFakeValues(1);
+  const writeFile = createWriteFile(fileName);
+  expect(testPromise.then(writeFile).then(fileExists)).resolves.not.toThrow();
+  expect(testPromise.then(writeFile).then(fileExists)).resolves.toEqual(true);
+});
+
+it('rejects an empty input', async () => {
+  const writeFile = createWriteFile('test_one.temp');
+  const testPromise = generateFakeValues(0);
+    expect(testPromise.then(writeFile)).rejects.toThrow();
+});
+
+/*
+  createShareData() is not tested, because it relies on the phoneGap social 
+  sharing plugin, which cannot be mocked.
+
+  getMyData relies on createShareData, and likewise cannot be tested - it also
+  relies on getRawEnteries().
+*/

www/js/controlHelper.ts

@@ -2,21 +2,9 @@ import { DateTime } from "luxon";
 
 import { getRawEntries } from "./commHelper";
 import { logInfo, displayError, logDebug } from "./plugin/logger";
+import { fsWindow } from "./types/fileIOTypes"
 import i18next from "./i18nextInit" ;
 
-interface fsWindow extends Window {
-  requestFileSystem: (
-    type: number,
-    size: number,
-    successCallback: (fs: any) => void,
-    errorCallback?: (error: any) => void
-  ) => void;
-  LocalFileSystem: {
-    TEMPORARY: number;
-    PERSISTENT: number;
-  };
-};
-
 declare let window: fsWindow;
 
 /**
@@ -65,6 +53,7 @@ export const createShareData = function(fileName: string, startTimeString: strin
     window.requestFileSystem(window.LocalFileSystem.TEMPORARY, 0, function(fs) {
       logDebug("During email, file system open: " + fs.name);
       fs.root.getFile(fileName, null, function(fileEntry) {
+        logDebug(`fileEntry is type ${typeof fileEntry.isFile}`)
         logDebug(`fileEntry ${fileEntry.nativeURL} is file? ${fileEntry.isFile.toString()}`);
         fileEntry.file(function(file) {
           const reader = new FileReader();

www/js/types/fileIOTypes.ts

@@ -0,0 +1,12 @@
+export interface fsWindow extends Window {
+  requestFileSystem: (
+    type: number,
+    size: number,
+    successCallback: (fs: any) => void,
+    errorCallback?: (error: any) => void
+  ) => void;
+  LocalFileSystem: {
+    TEMPORARY: number;
+    PERSISTENT: number;
+  };
+};