Improve compact numbers

Fixes #781

qa-include/app/format.php

@@ -2359,7 +2359,8 @@ function qa_favorite_form($entitytype, $entityid, $favorite, $title)
 
 /**
  * Format a number using the decimal point and thousand separator specified in the language files.
- * If the number is compacted it is turned into a string such as 1.3k or 2.5m.
+ * If the number is compacted it is turned into a string such as 17.3k (only the thousand/million
+ * cases are currently supported).
  *
  * @since 1.8.0
  * @param integer $number Number to be formatted
@@ -2374,20 +2375,15 @@ function qa_format_number($number, $decimals = 0, $compact = false)
 	$suffix = '';
 
 	if ($compact && qa_opt('show_compact_numbers')) {
-		$decimals = 0;
-		// only the k/m cases are currently supported (i.e. no billions)
+		// when compacting we keep 2-3 significant figures (e.g. 9.1k, 234k)
 		if ($number >= 1000000) {
 			$number /= 1000000;
 			$suffix = qa_lang_html('main/_millions_suffix');
+			$decimals = $number < 100 ? 1 : 0;
 		} elseif ($number >= 1000) {
 			$number /= 1000;
 			$suffix = qa_lang_html('main/_thousands_suffix');
-		}
-
-		// keep decimal part if not 0 and number is short (e.g. 9.1k)
-		$rounded = round($number, 1);
-		if ($number < 100 && ($rounded != (int)$rounded)) {
-			$decimals = 1;
+			$decimals = $number < 100 ? 1 : 0;
 		}
 	}
 

qa-tests/AppFormatTest.php

@@ -53,15 +53,15 @@ class AppFormatTest extends PHPUnit_Framework_TestCase
 		$qa_phrases_full['main']['_thousands_suffix'] = 'k';
 		$qa_phrases_full['main']['_millions_suffix'] = 'm';
 
-		// $decimal parameter ignored when 'show_compact_numbers' is true
-		$this->assertSame('5.5', qa_format_number(5.452, 0, true));
+		$this->assertSame('5', qa_format_number(5.452, 0, true));
 		$this->assertSame('5.5', qa_format_number(5.452, 1, true));
-		$this->assertSame('5', qa_format_number(5, 1, true));
+		$this->assertSame('5.0', qa_format_number(5, 1, true));
 
+		// $decimal parameter ignored when numbers are compacted
 		$this->assertSame('9.1k', qa_format_number(9123, 0, true));
 		$this->assertSame('9.1k', qa_format_number(9123, 1, true));
-		$this->assertSame('9k', qa_format_number(9040, 0, true));
-		$this->assertSame('9k', qa_format_number(9040, 1, true));
+		$this->assertSame('9.0k', qa_format_number(9040, 0, true));
+		$this->assertSame('9.0k', qa_format_number(9040, 1, true));
 		$this->assertSame('9.1k', qa_format_number(9050, 0, true));
 
 		$this->assertSame('123m', qa_format_number(123456789, 0, true));