Fixed #7405, small numbers in exponential notation were wrongly inter…

…preting decimals.
highcharts · Nov 21, 2017 · f613fe7 · f613fe7
1 parent 2ba2549
commit f613fe7
Show file tree

Hide file tree

Showing 2 changed files with 44 additions and 5 deletions.
diff --git a/js/parts/Utilities.js b/js/parts/Utilities.js
@@ -1418,17 +1418,36 @@ H.numberFormat = function (number, decimals, decimalPoint, thousandsSep) {
 		thousands,
 		ret,
 		roundedNumber,
-		exponent = number.toString().split('e');
+		exponent = number.toString().split('e'),
+		fractionDigits;
 
 	if (decimals === -1) {
 		// Preserve decimals. Not huge numbers (#3793).
 		decimals = Math.min(origDec, 20);
 	} else if (!H.isNumber(decimals)) {
 		decimals = 2;
-	} else if (decimals && exponent[1] && origDec - exponent[1] > decimals) {
+	} else if (decimals && exponent[1] && exponent[1] < 0) {
 		// Expose decimals from exponential notation (#7042)
-		exponent[0] *= Math.pow(10, exponent[1] - decimals);
-		exponent[1] = decimals;
+		fractionDigits = decimals + +exponent[1];
+		if (fractionDigits >= 0) {
+			// remove too small part of the number while keeping the notation
+			exponent[0] = (+exponent[0]).toExponential(fractionDigits)
+				.split('e')[0];
+			decimals = fractionDigits;
+		} else {
+			// fractionDigits < 0
+			exponent[0] = exponent[0].split('.')[0] || 0;
+
+			if (decimals < 20) {
+				// use number instead of exponential notation (#7405)
+				number = (exponent[0] * Math.pow(10, exponent[1]))
+					.toFixed(decimals);
+			} else {
+				// or zero
+				number = 0;
+			}
+			exponent[1] = 0;
+		}
 	}
 
 	// Add another decimal to avoid rounding errors of float numbers. (#4573)

diff --git a/samples/unit-tests/utilities/utilities/demo.js b/samples/unit-tests/utilities/utilities/demo.js
@@ -231,6 +231,7 @@
      * Test number formatting
      */
     QUnit.test('NumberFormat', function (assert) {
+        var i;
 
         assertEquals(assert, 'Integer with decimals', "1.00", numberFormat(1, 2));
         assertEquals(assert, 'Integer with decimal point', "1,0", numberFormat(1, 1, ','));
@@ -261,9 +262,28 @@
         assertEquals(
             assert,
             'Decimals limit with exponential (#7042)',
-            "0.00",
+            '0.00',
             numberFormat(1.5e-9, 2)
         );
+
+        // small numbers with set decimals (#7405)
+        for (i = 7; i < 11; i++) {
+            assertEquals(
+                assert,
+                'Decimals = ' + i + ' - precision to ' + i + 'th digit after .',
+                ['0.0000000', '0.00000000', '2e-9', '1.9e-9'][i - 7],
+                numberFormat(1.9e-9, i)
+            );
+        }
+
+        for (i = 6; i < 10; i++) {
+            assertEquals(
+                assert,
+                'Decimals = ' + i + ' - precision to ' + i + 'th digit after .',
+                ['0.000001', '6e-7', '6.3e-7', '6.26e-7'][i - 6],
+                numberFormat(6.26e-7, i)
+            );
+        }
     });