[WIP] Remove 26 lines of identical code in 4 locations

[Copilot]

Plan: Remove Code Duplication Using NestJS Best Practices

• Create a shared TimezoneFormatterService in the common directory
  • Extract the three duplicate methods: assertValidTimeZone, formatTimestamp, and getTimeZoneOffset
  • Make it an injectable NestJS service
• Create a CommonModule to provide the TimezoneFormatterService
• Update the four affected service files to use the shared service:
  • Update air.service.ts
  • Update soil.service.ts
  • Update traffic.service.ts
  • Update water.service.ts
• Create tests for the new TimezoneFormatterService
• Run existing tests to ensure no regression
• Run lint and build to verify code quality
• Request code review
• Run security scan

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Qlty: Found 26 lines of identical code in 4 locations (mass = 186)</issue_title>
<issue_description>Issue on Qlty

Found 26 lines of identical code in 4 locations (mass = 186)
Duplication
TypeScript
Medium
Found in 4 files
IgnoreOpen GitHub Issue
Found 26 lines of identical code in 4 locations (mass = 186)
src/air/air.service.ts

const
date =
new

Date
(value);

if
(
Number
.isNaN(date.getTime())) {

return
value;
}

if
(!timeZone) {

return
date.toISOString();
}

const
parts =
new

Intl
.DateTimeFormat(
'en-US'
, {
Found 26 lines of identical code in 4 locations (mass = 186)
src/soil/soil.service.ts

const
date =
new

Date
(value);

if
(
Number
.isNaN(date.getTime())) {

return
value;
}

if
(!timeZone) {

return
date.toISOString();
}

const
parts =
new

Intl
.DateTimeFormat(
'en-US'
, {
Found 26 lines of identical code in 4 locations (mass = 186)
src/traffic/traffic.service.ts

const
date =
new

Date
(value);

if
(
Number
.isNaN(date.getTime())) {

return
value;
}

if
(!timeZone) {

return
date.toISOString();
}

const
parts =
new

Intl
.DateTimeFormat(
'en-US'
, {
Found 26 lines of identical code in 4 locations (mass = 186)
src/water/water.service.ts

const
date =
new

Date
(value);

if
(
Number
.isNaN(date.getTime())) {

return
value;
}

if
(!timeZone) {

return
date.toISOString();
}

const
parts =
new

Intl
.DateTimeFormat(
'en-US'
, {</issue_description>

<agent_instructions>please resolve the code duplications using a consistant design pattern that is best practice for nestjs and ensure maintainability as the top priority.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Qlty: Found 26 lines of identical code in 4 locations (mass = 186) #6

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