Improve serialization

src/history/data/contents.js

@@ -12,5 +12,27 @@ export const parseRawResult = function (contents) {
 // Serialize the contents of a rawResult
 export const serializeRawResult = function (rawResult) {
   const contents = JSON.stringify(rawResult, undefined, 2)
-  return `${contents}\n`
+  const contentsA = flattenArray(contents)
+  return `${contentsA}\n`
 }
+
+// Some arrays like `histogram` and `quantiles` are big. `JSON.serialize()`
+// put each item in a separate line. We put those in a single line instead.
+//  - This makes it easier to view the file
+//  - This creates simpler git diffs
+//  - This creates better git stats when it comes to amount of lines changes
+// We only do this for arrays of simple types.
+const flattenArray = function (content) {
+  return content.replace(SIMPLE_ARRAY_REGEXP, flattenArrayItems)
+}
+
+// Matches `[...]` but not `[{ ... }]` nor `[[...]]`
+const SIMPLE_ARRAY_REGEXP = /(\[)([^[\]{]+)(\])/gmu
+
+// eslint-disable-next-line max-params
+const flattenArrayItems = function (_, start, match, end) {
+  const matchA = match.replace(WHITESPACES_REGEXP, ' ')
+  return `${start}${matchA}${end}`
+}
+
+const WHITESPACES_REGEXP = /\s+/gmu