feat: data pagination

src/constants/pagination.ts

@@ -0,0 +1,3 @@
+export const defaultOffset = 0
+export const defaultMaxLimit = 30
+export const defaultLimit = defaultMaxLimit / 2

src/modules/fares/fares.controller.ts

@@ -1,5 +1,6 @@
 import { Controller, Get, Query } from '@nestjs/common'
 
+import { defaultLimit, defaultOffset } from '../../constants/pagination.js'
 import { ListFaresQueryDto } from './fares.dto.js'
 import { FaresService } from './fares.service.js'
 
@@ -8,7 +9,15 @@ export class FaresController {
   constructor(private readonly fareService: FaresService) {}
 
   @Get()
-  listFares(@Query() { from, to }: ListFaresQueryDto) {
-    return this.fareService.listFares({ from, to })
+  listFares(
+    @Query()
+    {
+      from,
+      to,
+      offset = defaultOffset,
+      limit = defaultLimit,
+    }: ListFaresQueryDto
+  ) {
+    return this.fareService.listFares({ from, to, offset, limit })
   }
 }

src/modules/fares/fares.dto.ts

@@ -1,12 +1,34 @@
-import { IsEnum, IsOptional } from 'class-validator'
+import { ArgsType, Field, Int } from '@nestjs/graphql'
+import { Type } from 'class-transformer'
+import { IsEnum, IsInt, IsOptional, Max, Min } from 'class-validator'
 import { StopCode } from 'mtr-kit'
 
+import { defaultMaxLimit } from '../../constants/pagination.js'
+
+@ArgsType()
 export class ListFaresQueryDto {
   @IsEnum(StopCode)
   @IsOptional()
+  @Field(() => StopCode, { nullable: true })
   from?: StopCode
 
   @IsEnum(StopCode)
   @IsOptional()
+  @Field(() => StopCode, { nullable: true })
   to?: StopCode
+
+  @Type(() => Number)
+  @IsInt()
+  @Min(0)
+  @IsOptional()
+  @Field(() => Int, { nullable: true })
+  offset?: number
+
+  @Type(() => Number)
+  @IsInt()
+  @Max(defaultMaxLimit)
+  @Min(0)
+  @IsOptional()
+  @Field(() => Int, { nullable: true })
+  limit?: number
 }

src/modules/fares/fares.resolver.ts

@@ -1,6 +1,7 @@
 import { Args, Query, Resolver } from '@nestjs/graphql'
-import { StopCode } from 'mtr-kit'
 
+import { defaultLimit, defaultOffset } from '../../constants/pagination.js'
+import { ListFaresQueryDto } from './fares.dto.js'
 import { Fare } from './fares.model.js'
 import { FaresService } from './fares.service.js'
 
@@ -10,9 +11,14 @@ export class FaresResolver {
 
   @Query(() => [Fare])
   fares(
-    @Args('from', { type: () => StopCode, nullable: true }) from: StopCode,
-    @Args('to', { type: () => StopCode, nullable: true }) to: StopCode
+    @Args()
+    {
+      from,
+      to,
+      offset = defaultOffset,
+      limit = defaultLimit,
+    }: ListFaresQueryDto
   ) {
-    return this.faresService.listFares({ from, to })
+    return this.faresService.listFares({ from, to, offset, limit })
   }
 }

src/modules/fares/fares.service.ts

@@ -1,6 +1,7 @@
 import { Injectable } from '@nestjs/common'
 import { Interval, Timeout } from '@nestjs/schedule'
 import { LineCode, StopCode, fareApi, stops } from 'mtr-kit'
+import { drop, take } from 'ramda'
 
 import { normalizeStopName } from '../../utils/normalizeStopName.js'
 
@@ -116,10 +117,24 @@ export class FaresService {
     this.fares = [...mtrFares, ...airportExpressFares]
   }
 
-  async listFares({ from, to }: { from?: StopCode; to?: StopCode }) {
-    return this.fares.filter(
+  async listFares({
+    from,
+    to,
+    offset,
+    limit,
+  }: {
+    from?: StopCode
+    to?: StopCode
+    offset?: number
+    limit?: number
+  }) {
+    const res = this.fares.filter(
       item => (!from || item.from === from) && (!to || item.to === to)
     )
+
+    const withOffset = offset ? drop(offset, res) : res
+    const withLimit = limit ? take(limit, withOffset) : withOffset
+    return withLimit
   }
 
   listLineStopFares(_: LineCode, stop: StopCode) {

src/modules/lines/lines.controller.ts

@@ -1,7 +1,9 @@
-import { Controller, Get, Param } from '@nestjs/common'
+import { Controller, Get, Param, Query } from '@nestjs/common'
 import { LineCode, StopCode } from 'mtr-kit'
 
+import { defaultLimit, defaultOffset } from '../../constants/pagination.js'
 import { SchedulesService } from '../schedules/schedules.service.js'
+import { ListLinesQueryDto } from './lines.dto.js'
 import { LinesService } from './lines.service.js'
 
 @Controller('/api/v1/lines')
@@ -12,8 +14,11 @@ export class LinesController {
   ) {}
 
   @Get()
-  listLines() {
-    return this.linesService.listLines()
+  listLines(
+    @Query()
+    { offset = defaultOffset, limit = defaultLimit }: ListLinesQueryDto
+  ) {
+    return this.linesService.listLines({ offset, limit })
   }
 
   @Get(':line')

src/modules/lines/lines.dto.ts

@@ -0,0 +1,23 @@
+import { ArgsType, Field, Int } from '@nestjs/graphql'
+import { Type } from 'class-transformer'
+import { IsInt, IsOptional, Max, Min } from 'class-validator'
+
+import { defaultMaxLimit } from '../../constants/pagination.js'
+
+@ArgsType()
+export class ListLinesQueryDto {
+  @Type(() => Number)
+  @IsInt()
+  @Min(0)
+  @IsOptional()
+  @Field(() => Int, { nullable: true })
+  offset?: number
+
+  @Type(() => Number)
+  @IsInt()
+  @Max(defaultMaxLimit)
+  @Min(0)
+  @IsOptional()
+  @Field(() => Int, { nullable: true })
+  limit?: number
+}

src/modules/lines/lines.resolver.ts

@@ -1,8 +1,10 @@
 import { Args, Parent, Query, ResolveField, Resolver } from '@nestjs/graphql'
 import { LineCode, StopCode } from 'mtr-kit'
 
+import { defaultLimit, defaultOffset } from '../../constants/pagination.js'
 import { Schedule } from '../schedules/schedules.model.js'
 import { SchedulesService } from '../schedules/schedules.service.js'
+import { ListLinesQueryDto } from './lines.dto.js'
 import { Line, LineStop } from './lines.model.js'
 import { LinesService } from './lines.service.js'
 
@@ -11,8 +13,11 @@ export class LinesResolver {
   constructor(private readonly linesService: LinesService) {}
 
   @Query(() => [Line])
-  lines() {
-    return this.linesService.listLines()
+  lines(
+    @Args()
+    { offset = defaultOffset, limit = defaultLimit }: ListLinesQueryDto
+  ) {
+    return this.linesService.listLines({ offset, limit })
   }
 
   @Query(() => Line)

src/modules/lines/lines.service.ts

@@ -1,11 +1,15 @@
 import { Injectable } from '@nestjs/common'
 import { LineCode, StopCode, lineMap, lines } from 'mtr-kit'
-import { omit } from 'ramda'
+import { drop, omit, take } from 'ramda'
 
 @Injectable()
 export class LinesService {
-  listLines() {
-    return lines.map(omit(['stops']))
+  listLines({ offset, limit }: { offset?: number; limit?: number }) {
+    const res = lines.map(omit(['stops']))
+
+    const withOffset = offset ? drop(offset, res) : res
+    const withLimit = limit ? take(limit, withOffset) : withOffset
+    return withLimit
   }
 
   getLine({ line }: { line: LineCode }) {

src/modules/schedules/schedules.controller.ts

@@ -1,13 +1,23 @@
-import { Controller, Get } from '@nestjs/common'
+import { Controller, Get, Query } from '@nestjs/common'
 
+import { defaultLimit, defaultOffset } from '../../constants/pagination.js'
+import { ListSchedulesQueryDto } from './schedules.dto.js'
 import { SchedulesService } from './schedules.service.js'
 
 @Controller('/api/v1/schedules')
 export class SchedulesController {
   constructor(private readonly schedulesService: SchedulesService) {}
 
   @Get()
-  listSchedules() {
-    return this.schedulesService.listSchedules()
+  listSchedules(
+    @Query()
+    {
+      line,
+      stop,
+      offset = defaultOffset,
+      limit = defaultLimit,
+    }: ListSchedulesQueryDto
+  ) {
+    return this.schedulesService.listSchedules({ line, stop, offset, limit })
   }
 }

src/modules/schedules/schedules.dto.ts

@@ -0,0 +1,34 @@
+import { ArgsType, Field, Int } from '@nestjs/graphql'
+import { Type } from 'class-transformer'
+import { IsEnum, IsInt, IsOptional, Max, Min } from 'class-validator'
+import { LineCode, StopCode } from 'mtr-kit'
+
+import { defaultMaxLimit } from '../../constants/pagination.js'
+
+@ArgsType()
+export class ListSchedulesQueryDto {
+  @IsEnum(LineCode)
+  @IsOptional()
+  @Field(() => LineCode, { nullable: true })
+  line?: LineCode
+
+  @IsEnum(StopCode)
+  @IsOptional()
+  @Field(() => StopCode, { nullable: true })
+  stop?: StopCode
+
+  @Type(() => Number)
+  @IsInt()
+  @Min(0)
+  @IsOptional()
+  @Field(() => Int, { nullable: true })
+  offset?: number
+
+  @Type(() => Number)
+  @IsInt()
+  @Max(defaultMaxLimit)
+  @Min(0)
+  @IsOptional()
+  @Field(() => Int, { nullable: true })
+  limit?: number
+}

src/modules/schedules/schedules.resolver.ts

@@ -1,5 +1,7 @@
-import { Query, Resolver } from '@nestjs/graphql'
+import { Args, Query, Resolver } from '@nestjs/graphql'
 
+import { defaultLimit, defaultOffset } from '../../constants/pagination.js'
+import { ListSchedulesQueryDto } from './schedules.dto.js'
 import { Schedule } from './schedules.model.js'
 import { SchedulesService } from './schedules.service.js'
 
@@ -8,7 +10,15 @@ export class SchedulesResolver {
   constructor(private readonly schedulesService: SchedulesService) {}
 
   @Query(() => [Schedule])
-  stops() {
-    return this.schedulesService.listSchedules()
+  schedules(
+    @Args()
+    {
+      line,
+      stop,
+      offset = defaultOffset,
+      limit = defaultLimit,
+    }: ListSchedulesQueryDto
+  ) {
+    return this.schedulesService.listSchedules({ line, stop, offset, limit })
   }
 }

src/modules/schedules/schedules.service.ts

@@ -1,5 +1,6 @@
 import { Injectable } from '@nestjs/common'
 import { LineCode, StopCode, lineMap, lines } from 'mtr-kit'
+import { drop, take } from 'ramda'
 
 import { NormalizedSchedule, scheduleMap } from '../../worker.js'
 
@@ -22,31 +23,34 @@ export class SchedulesService {
       .filter((v): v is NonNullable<typeof v> => Boolean(v))
   }
 
-  listStopSchedules({ stop }: { stop: StopCode }) {
-    return lines
-      .filter(line => line.stops.some(item => item.stop === stop))
-      .reduce<({ line: LineCode } & NormalizedSchedule)[]>(
-        (acc, { line }) => [
+  listSchedules({
+    line,
+    stop,
+    offset,
+    limit,
+  }: {
+    line?: LineCode
+    stop?: StopCode
+    offset?: number
+    limit?: number
+  }) {
+    const res = lines
+      .reduce<({ line: LineCode; stop: StopCode } & NormalizedSchedule)[]>(
+        (acc, item) => [
           ...acc,
-          ...this.listLineStopSchedules({ line, stop }),
+          ...this.listLineSchedules({ line: item.line }).map(scheduleItem => ({
+            line: item.line,
+            ...scheduleItem,
+          })),
         ],
         []
       )
-      .filter((v): v is NonNullable<typeof v> => Boolean(v))
-  }
+      .filter(
+        item => (!line || item.line === line) && (!stop || item.stop === stop)
+      )
 
-  listSchedules() {
-    return lines.reduce<
-      ({ line: LineCode; stop: StopCode } & NormalizedSchedule)[]
-    >(
-      (acc, { line }) => [
-        ...acc,
-        ...this.listLineSchedules({ line }).map(item => ({
-          line,
-          ...item,
-        })),
-      ],
-      []
-    )
+    const withOffset = offset ? drop(offset, res) : res
+    const withLimit = limit ? take(limit, withOffset) : withOffset
+    return withLimit
   }
 }