Fix counting of changes for impactful stats like file size

Author: bartveneman

src/index.js

@@ -11,15 +11,21 @@ module.exports = diff => {
 			}
 
 			// Numeric diff (total rules, file size)
+			// Only return *that* something has changed, not how much,
+			// because the impact can differ greatly depending on the
+			// metric. File size usually changes more than # of rules.
 			if (value.diff) {
 				return {
-					changes: Math.abs(value.diff.absolute),
-					additions: value.diff.absolute > 0 ? value.diff.absolute : 0,
-					deletions: value.diff.absolute < 0 ? Math.abs(value.diff.absolute) : 0
+					changes: Math.abs(value.diff.absolute) > 0 ? 1 : 0,
+					additions: value.diff.absolute > 0 ? 1 : 0,
+					deletions: value.diff.absolute < 0 ? 1 : 0
 				}
 			}
 
-			// Strings and complicated structures
+			// Strings and complicated structures.
+			// Always return that the value has changed, as both an
+			// addition and a deletion: the old value has been
+			// deleted and a new one has been added.
 			return {
 				changes: value.changed ? 1 : 0,
 				additions: value.changed ? 1 : 0,

test/index.js

@@ -105,6 +105,18 @@ test('it counts the correct amount of changes for numbers', t => {
 				additions: 0,
 				deletions: 1
 			}
+		],
+		[
+			{
+				'stylesheets.size': {
+					diff: {absolute: 123456789}
+				}
+			},
+			{
+				changes: 1,
+				additions: 1,
+				deletions: 0
+			}
 		]
 	]
 
@@ -130,7 +142,7 @@ test('it handles multiple types of stats correctly', t => {
 			{
 				'colors.total': {diff: {absolute: 2}},
 				'rules.total': {diff: {absolute: -1}},
-				'selectors.identifiers.max.value': {changed: true},
+				'selectors.identifiers.max.value': {changed: true}, // 1 deletion, 1 addition
 				'colors.unique': [
 					{
 						added: true,
@@ -145,8 +157,8 @@ test('it handles multiple types of stats correctly', t => {
 				]
 			},
 			{
-				changes: 5,
-				additions: 4,
+				changes: 4,
+				additions: 3,
 				deletions: 2
 			}
 		]