fix(tui): roll the compact form over to M at the rounding boundary (#55871)

Co-authored-by: argszero <argszero@users.noreply.github.com>
Co-authored-by: Tarquinen <78942835+Tarquinen@users.noreply.github.com>

packages/tui/src/util/locale.ts

@@ -17,7 +17,8 @@ export function datetime(input: number): string {
 }
 
 export function number(num: number): string {
-  if (num >= 1000000) {
+  // 999950+ would round to "1000.0K"
+  if (num >= 999950) {
     return (num / 1000000).toFixed(1) + "M"
   } else if (num >= 1000) {
     return (num / 1000).toFixed(1) + "K"

packages/tui/test/util/locale.test.ts

@@ -12,3 +12,9 @@ test("takes whole graphemes within terminal width", () => {
   expect(Locale.takeWidth("ab界cd", 4)).toBe("ab界")
   expect(Locale.graphemes("a👨‍👩‍👧‍👦b")).toEqual(["a", "👨‍👩‍👧‍👦", "b"])
 })
+
+test("rolls the compact form over at the rounding boundary", () => {
+  expect(Locale.number(999949)).toBe("999.9K")
+  expect(Locale.number(999950)).toBe("1.0M")
+  expect(Locale.number(1000000)).toBe("1.0M")
+})