build: include empty releases in changelog and fix commit grouping

Author: Planeshifter

lib/node_modules/@stdlib/_tools/changelog/generate/lib/main.js

@@ -58,6 +58,7 @@ var STDLIB_REPO_NODE_PATH = 'https://github.com/stdlib-js/stdlib/tree/develop/li
 var RE_PACKAGE_SUBDIRS = /\/?(benchmark|bin|data|docs|etc|examples|include|lib|scripts|src|test)\/?[\s\S]*$/;
 var RE_MARKDOWN_HEADER = /(^#+)/gm;
 var RE_EXTRANEOUS_NEWLINES = /\n{3,}/g;
+var PLACEHOLDER_SUMMARY = 'No changes reported for this release.';
 
 
 // FUNCTIONS //
@@ -348,7 +349,7 @@ function generate( pkg, releaseType ) {
 			version = releases[ i ][ 0 ];
 			releaseCommits = commits[ version ];
 			if ( !releaseCommits ) {
-				continue;
+				releaseCommits = [];
 			}
 			str += '## ' + version + ' (' + formatDate( releases[ i ][ 1 ] ) + ')\n\n';
 			bySubpackage = groupBySubPackage( releaseCommits, pkg );
@@ -359,7 +360,7 @@ function generate( pkg, releaseType ) {
 				name = pkgNames[ j ];
 				summary = releaseSummary( bySubpackage[ name ], true, true );
 				if ( !summary ) {
-					continue;
+					summary = PLACEHOLDER_SUMMARY;
 				}
 				str += packageSummaryWrapper( pkg, version, name, summary );
 			}
@@ -374,7 +375,7 @@ function generate( pkg, releaseType ) {
 			version = releases[ i ][ 0 ];
 			summary = releaseSummary( commits[ version ] );
 			if ( !summary ) {
-				continue;
+				summary = PLACEHOLDER_SUMMARY;
 			}
 			str += releaseSectionStart( version );
 			str += '## ' + version + ' (' + formatDate( releases[ i ][ 1 ] ) + ')\n\n';
@@ -395,13 +396,19 @@ function generate( pkg, releaseType ) {
 	* @returns {string} release indicator
 	*/
 	function indicator( commit ) {
+		var prevReleaseDate;
+		var releaseDate;
 		var date;
 		var i;
 		date = new Date( commit.date );
 
 		// Walk the releases in reverse chronological order:
 		for ( i = releases.length-1; i >= 0; i-- ) {
-			if ( date <= new Date( releases[ i ][ 1 ] ) ) {
+			releaseDate = new Date( releases[ i ][ 1 ] );
+
+			// Get the previous release date or set it to a very early date if none exists:
+			prevReleaseDate = ( i > 0 ) ? new Date( releases[ i-1 ][ 1 ] ) : new Date( 0 );
+			if ( date <= releaseDate && date > prevReleaseDate ) {
 				return releases[ i ][ 0 ]; // version
 			}
 		}