Add init code to check whether an update is available

js/version.js

@@ -2,7 +2,7 @@
  * Handle version related methods
  */
 
-const VERSION = "v0.5"
+const VERSION = "0.5"
 
 
 function populateVersionInSettings() {
@@ -26,5 +26,94 @@ function generateVersionString(version) {
  * @returns {string} - Returns a generated string to be used to show the version
  * and the product name.
  */
- return `startpage - ${version}`
+ return `startpage - v${version}`
+}
+
+
+async function checkIfUpdateAvailable() {
+ /**
+ * Check if a new version is available from the current version.
+ * 
+ * We will essentially hit GitHub API to fetch the latest tag and
+ * check if that tag is higher than the current hardcoded version.
+ */
+ latestTagAvailable = await getGithubReleaseTag();
+
+ // We need to compare the tags to see if the tag available is older than
+ // the current one
+ isUpdateAvailable = isTagHigher(latestTagAvailable, VERSION);
+}
+
+
+async function getGithubReleaseTag() {
+ /**
+ * Hit GitHub API to fetch the latest release tag for the repo
+ */
+ const URL = "https://api.github.com/repos/deepjyoti30/startpage/releases/latest"
+
+ var response = await fetch(URL);
+ var responseJSON = await response.json();
+
+ var tagName = responseJSON.tag_name;
+
+ // NOTE: Sometimes (due to personal mistakes), the tag might contain a `v` prefix
+ // so we will need to remove it before returning the value.
+ if (tagName.charAt(0) == "v") {
+ tagName = tagName.slice(1, tagName.length);
+ }
+
+ return tagName;
+}
+
+
+function isTagHigher(newerTag, olderTag) {
+ /**
+ * Check if the newer tag is higher than the older tag.
+ */
+ var newerTagSplitted = newerTag.split(".");
+ var olderTagSplitted = olderTag.split(".");
+
+ // We want to make both the arrays of same length and all the non
+ // existent digits will be 0.
+ if (newerTagSplitted.length != olderTagSplitted.length) {
+ if (newerTagSplitted.length > olderTagSplitted.length) {
+ // Older tag is shorter
+ //
+ // Reverse and add 0 till the lengths become same
+ // and then reverse it back.
+ var olderTagReversed = olderTagSplitted.reverse();
+ const shorterBy = newerTagSplitted.length - olderTagSplitted.length;
+
+ for(var i = 0; i < shorterBy; i++) {
+ olderTagReversed.push('0');
+ }
+
+ olderTagSplitted = olderTagReversed.reverse();
+ } else {
+ var newerTagReversed = newerTagSplitted.reverse();
+ const shorterBy = olderTagSplitted.length - newerTagSplitted.length;
+
+ for(var i = 0; i < shorterBy; i++) {
+ newerTagReversed.push('0');
+ }
+
+ newerTagSplitted = newerTagReversed.reverse();
+ }
+ }
+
+ // At this point both arrays should be of same length and we
+ // can easily compare them to see which one is larger.
+ var isNewerHigher = false;
+
+ for(var i = 0; i < newerTagSplitted.length; i++) {
+ newerDigit = parseInt(newerTagSplitted[i]);
+ olderDigit = parseInt(olderTagSplitted[i]);
+
+ if (newerDigit > olderDigit) {
+ isNewerHigher = true;
+ break;
+ }
+ }
+
+ return isNewerHigher;
 }