refactor: replace ignored numeric literals with constants

src/modules/investments/income/income-analytics.service.ts

@@ -30,6 +30,8 @@ import {
   rangeBuckets,
 } from './income-period';
 
+const STALE_FRESHNESS_MS = 0;
+
 type Total = {
   coupon: ReturnType<typeof decimalFromString>;
   dividend: ReturnType<typeof decimalFromString>;
@@ -120,7 +122,7 @@ export class IncomeAnalyticsService {
         fetchedAt: current.meta.lastSuccessfulAt ?
             new Date(current.meta.lastSuccessfulAt) :
           null,
-        freshForMs: current.meta.freshness === 'fresh' ? Infinity : 0,
+        freshForMs: current.meta.freshness === 'fresh' ? Infinity : STALE_FRESHNESS_MS,
         work: work?.id ? { ...work, id: work.id } : null,
         coverage: current.meta.coverage,
         dependencies,

src/modules/investments/income/income-period.ts

@@ -1,6 +1,6 @@
 import { BadRequestException } from '@nestjs/common';
 
-import { MILLISECONDS_PER_DAY } from '../../../common/time';
+import { ISO_DATE_LENGTH, ISO_DATE_START, MILLISECONDS_PER_DAY } from '../../../common/time';
 import {
   DateOnlyRange,
   dateParts,
@@ -8,6 +8,14 @@ import {
   utcDate,
 } from '../investment-calendar';
 
+const MONDAY_WEEKDAY_INDEX = 1;
+const INCLUSIVE_DAY_OFFSET = 1;
+const NEXT_DAY_OFFSET = 1;
+const PREVIOUS_MONTH_LAST_DAY = 0;
+const PREVIOUS_DAY_OFFSET = -1;
+const PREVIOUS_YEAR_OFFSET = 1;
+const DATE_COMPONENT_DIGITS = 2;
+
 const DAILY_BUCKET_MAX_DAYS = 45;
 const WEEKLY_BUCKET_MAX_DAYS = 180;
 const DAYS_PER_WEEK = 7;
@@ -65,21 +73,21 @@ export function rangeBuckets(
         addDays(
           range.from,
           -(
-            (utcDate(range.from).getUTCDay() + DAYS_PER_WEEK - 1) %
+            (utcDate(range.from).getUTCDay() + DAYS_PER_WEEK - MONDAY_WEEKDAY_INDEX) %
             DAYS_PER_WEEK
           ),
         ) :
-      `${range.from.slice(0, ISO_MONTH_LENGTH)}-01`;
+      `${range.from.slice(ISO_DATE_START, ISO_MONTH_LENGTH)}-01`;
   while (cursor <= range.to) {
     const end =
       granularity === 'week' ?
-          addDays(cursor, DAYS_PER_WEEK - 1) :
+          addDays(cursor, DAYS_PER_WEEK - INCLUSIVE_DAY_OFFSET) :
           endOfMonth(cursor);
     buckets.push({
       from: cursor < range.from ? range.from : cursor,
       to: end > range.to ? range.to : end,
     });
-    cursor = addDays(end, 1);
+    cursor = addDays(end, NEXT_DAY_OFFSET);
   }
   return buckets;
 }
@@ -89,7 +97,7 @@ export function rangeDays(range: DateOnlyRange): number {
     Math.round(
       (utcDate(range.to).valueOf() - utcDate(range.from).valueOf()) /
       MILLISECONDS_PER_DAY,
-    ) + 1
+    ) + INCLUSIVE_DAY_OFFSET
   );
 }
 
@@ -106,24 +114,24 @@ function assertRange(range: DateOnlyRange, today: string): void {
 function addDays(value: string, days: number): string {
   const date = utcDate(value);
   date.setUTCDate(date.getUTCDate() + days);
-  return date.toISOString().slice(0, 10);
+  return date.toISOString().slice(ISO_DATE_START, ISO_DATE_LENGTH);
 }
 
 function dates(range: DateOnlyRange): string[] {
   const result: string[] = [];
-  for (let date = range.from; date <= range.to; date = addDays(date, 1)) {
+  for (let date = range.from; date <= range.to; date = addDays(date, NEXT_DAY_OFFSET)) {
     result.push(date);
   }
   return result;
 }
 
 function firstOfMonth(value: string): string {
-  return `${value.slice(0, ISO_MONTH_LENGTH)}-01`;
+  return `${value.slice(ISO_DATE_START, ISO_MONTH_LENGTH)}-01`;
 }
 
 function endOfMonth(value: string): string {
   const [year, month] = dateParts(firstOfMonth(value));
-  return new Date(Date.UTC(year, month, 0)).toISOString().slice(0, 10);
+  return new Date(Date.UTC(year, month, PREVIOUS_MONTH_LAST_DAY)).toISOString().slice(ISO_DATE_START, ISO_DATE_LENGTH);
 }
 
 function isFullMonth(range: DateOnlyRange): boolean {
@@ -133,7 +141,7 @@ function isFullMonth(range: DateOnlyRange): boolean {
 }
 
 function previousMonth(from: string): DateOnlyRange {
-  const last = addDays(firstOfMonth(from), -1);
+  const last = addDays(firstOfMonth(from), PREVIOUS_DAY_OFFSET);
   return { from: firstOfMonth(last), to: last };
 }
 
@@ -144,8 +152,8 @@ function shiftDays(range: DateOnlyRange, days: number): DateOnlyRange {
 function yearAgo(range: DateOnlyRange): DateOnlyRange | null {
   const shift = (value: string) => {
     const [year, month, day] = dateParts(value);
-    const result = `${String(year - 1).padStart(ISO_YEAR_LENGTH, '0')}-${String(month).padStart(2, '0')}-${String(day).padStart(2, '0')}`;
-    return utcDate(result).toISOString().slice(0, 10) === result ?
+    const result = `${String(year - PREVIOUS_YEAR_OFFSET).padStart(ISO_YEAR_LENGTH, '0')}-${String(month).padStart(DATE_COMPONENT_DIGITS, '0')}-${String(day).padStart(DATE_COMPONENT_DIGITS, '0')}`;
+    return utcDate(result).toISOString().slice(ISO_DATE_START, ISO_DATE_LENGTH) === result ?
       result :
       null;
   };