feat(api): Add pagination metadata to Environment module

apps/api/src/common/paginate.spec.ts

@@ -0,0 +1,93 @@
+import { paginate } from './paginate'
+
+describe('paginate', () => {
+  it('should paginate without default query', () => {
+    const totalCount = 100
+    const relativeUrl = '/items'
+    const query = { page: 2, limit: 10 }
+
+    const result = paginate(totalCount, relativeUrl, query)
+
+    expect(result).toBeDefined()
+    expect(result).toEqual(
+      expect.objectContaining({
+        page: 2,
+        perPage: 10,
+        pageCount: 10,
+        totalCount: 100
+      })
+    )
+    expect(result.links.self).toEqual('/items?page=2&limit=10')
+    expect(result.links.first).toEqual('/items?page=0&limit=10')
+    expect(result.links.previous).toEqual('/items?page=1&limit=10')
+    expect(result.links.next).toEqual('/items?page=3&limit=10')
+    expect(result.links.last).toEqual('/items?page=9&limit=10')
+  })
+
+  it('should paginate with default query', () => {
+    const totalCount = 100
+    const relativeUrl = '/items'
+    const query = { page: 5, limit: 10 }
+    const defaultQuery = { pricing: 'pro', filter: 'admin' }
+
+    const result = paginate(totalCount, relativeUrl, query, defaultQuery)
+
+    expect(result).toBeDefined()
+    expect(result).toEqual(
+      expect.objectContaining({
+        page: 5,
+        perPage: 10,
+        pageCount: 10,
+        totalCount: 100
+      })
+    )
+    expect(result.links.self).toEqual(
+      '/items?filter=admin&pricing=pro&page=5&limit=10'
+    )
+    expect(result.links.first).toEqual(
+      '/items?filter=admin&pricing=pro&page=0&limit=10'
+    )
+    expect(result.links.previous).toEqual(
+      '/items?filter=admin&pricing=pro&page=4&limit=10'
+    )
+    expect(result.links.next).toEqual(
+      '/items?filter=admin&pricing=pro&page=6&limit=10'
+    )
+    expect(result.links.last).toEqual(
+      '/items?filter=admin&pricing=pro&page=9&limit=10'
+    )
+  })
+
+  it('should paginate correctly edge cases where pervious or next is null', () => {
+    const totalCount = 10
+    const relativeUrl = '/items'
+    const query = { page: 0, limit: 10 }
+
+    const result = paginate(totalCount, relativeUrl, query)
+
+    expect(result).toBeDefined()
+    expect(result).toEqual(
+      expect.objectContaining({
+        page: 0,
+        perPage: 10,
+        pageCount: 1,
+        totalCount: 10
+      })
+    )
+    expect(result.links.self).toEqual('/items?page=0&limit=10')
+    expect(result.links.first).toEqual('/items?page=0&limit=10')
+    expect(result.links.previous).toBeNull()
+    expect(result.links.next).toBeNull()
+    expect(result.links.last).toEqual('/items?page=0&limit=10')
+  })
+
+  it('should not be able to paginate when limit is 0 or undefined', () => {
+    const totalCount = 10
+    const relativeUrl = '/items'
+    const query = { page: 0, limit: 0 }
+
+    expect(() => paginate(totalCount, relativeUrl, query)).toThrow(
+      'Limit is required'
+    )
+  })
+})

apps/api/src/common/paginate.ts

@@ -0,0 +1,75 @@
+export interface PaginatedMetadata {
+  page: number
+  perPage: number
+  pageCount: number
+  totalCount: number
+  links: {
+    self: string
+    first: string
+    previous: string | null
+    next: string | null
+    last: string
+  }
+}
+
+interface QueryOptions {
+  page: number
+  limit: number
+  sort?: string
+  order?: string
+  search?: string
+}
+
+//convert query object to query string to use in links
+const getQueryString = (query: QueryOptions) => {
+  return Object.keys(query)
+    .map((key) => `${key}=${query[key]}`)
+    .join('&')
+}
+
+export const paginate = (
+  totalCount: number,
+  relativeUrl: string,
+  query: QueryOptions,
+  defaultQuery?: Record<string, any>
+) => {
+  //query.limit cannot be 0 or undefined
+  if (!query.limit) throw new Error('Limit is required')
+  let defaultQueryStr = ''
+  if (defaultQuery) {
+    //sorting entries to make sure the order is consistent and predictable during tests
+    const sortedEntries = Object.entries(defaultQuery).sort(([keyA], [keyB]) =>
+      keyA.localeCompare(keyB)
+    )
+    //ignore keys with undefined values. Undefined values may occur when qury params are optional
+    defaultQueryStr = sortedEntries.reduce((res, [key, value]) => {
+      if (value !== undefined) {
+        res += `${key}=${value}&`
+      }
+      return res
+    }, '')
+  }
+
+  const metadata = {} as PaginatedMetadata
+  metadata.page = query.page
+  metadata.perPage = query.limit
+  metadata.pageCount = Math.ceil(totalCount / query.limit)
+  metadata.totalCount = totalCount
+
+  //create links from relativeUrl , defalutQueryStr and query of type QueryOptions
+  metadata.links = {
+    self: `${relativeUrl}?${defaultQueryStr + getQueryString(query)}`,
+    first: `${relativeUrl}?${defaultQueryStr + getQueryString({ ...query, page: 0 })}`,
+    previous:
+      query.page === 0
+        ? null
+        : `${relativeUrl}?${defaultQueryStr + getQueryString({ ...query, page: query.page - 1 })}`,
+    next:
+      query.page === metadata.pageCount - 1
+        ? null
+        : `${relativeUrl}?${defaultQueryStr + getQueryString({ ...query, page: query.page + 1 })}`,
+    last: `${relativeUrl}?${defaultQueryStr + getQueryString({ ...query, page: metadata.pageCount - 1 })}`
+  }
+
+  return metadata
+}

apps/api/src/environment/service/environment.service.ts

@@ -17,6 +17,7 @@ import { UpdateEnvironment } from '../dto/update.environment/update.environment'
 import { PrismaService } from '../../prisma/prisma.service'
 import createEvent from '../../common/create-event'
 import { AuthorityCheckerService } from '../../common/authority-checker.service'
+import { paginate } from '../../common/paginate'
 
 @Injectable()
 export class EnvironmentService {
@@ -171,8 +172,8 @@ export class EnvironmentService {
       prisma: this.prisma
     })
 
-    // Get the environments
-    return await this.prisma.environment.findMany({
+    // Get the environments for the required page
+    const items = await this.prisma.environment.findMany({
       where: {
         projectId,
         name: {
@@ -195,11 +196,29 @@ export class EnvironmentService {
         }
       },
       skip: page * limit,
-      take: limit,
+      take: Number(limit),
       orderBy: {
         [sort]: order
       }
     })
+    // Calculate metadata for pagination
+    const totalCount = await this.prisma.environment.count({
+      where: {
+        projectId,
+        name: {
+          contains: search
+        }
+      }
+    })
+    const metadata = paginate(totalCount, `/environment/all/${projectId}`, {
+      page: Number(page),
+      limit: Number(limit),
+      sort,
+      order,
+      search
+    })
+
+    return { items, metadata }
   }
 
   async deleteEnvironment(user: User, environmentId: Environment['id']) {

packages/api-client/src/types/environment.types.d.ts

@@ -67,6 +67,19 @@ export interface GetAllEnvironmentsOfProjectResponse {
       profilePictureUrl: string | null
     }
   }[]
+  metadata: {
+    page: number
+    perPage: number
+    pageCount: number
+    totalCount: number
+    links: {
+      self: string
+      first: string
+      previous: string | null
+      next: string | null
+      last: string
+    }
+  }
 }
 
 export interface DeleteEnvironmentRequest {

packages/api-client/tests/environment.spec.ts

@@ -87,8 +87,20 @@ describe('Get Environments Tests', () => {
           }
         )
 
-      expect(environments).toHaveLength(2)
-      expect(environments[0].name).toBe('Default')
+      expect(environments.items).toHaveLength(2)
+      expect(environments.items[0].name).toBe('Default')
+      expect(environments.metadata.totalCount).toEqual(2)
+      expect(environments.metadata.links.self).toBe(
+        `/environment/all/${projectId}?page=0&limit=10&sort=name&order=asc&search=`
+      )
+      expect(environments.metadata.links.first).toBe(
+        `/environment/all/${projectId}?page=0&limit=10&sort=name&order=asc&search=`
+      )
+      expect(environments.metadata.links.previous).toBeNull()
+      expect(environments.metadata.links.next).toBeNull()
+      expect(environments.metadata.links.last).toBe(
+        `/environment/all/${projectId}?page=0&limit=10&sort=name&order=asc&search=`
+      )
     } catch (error) {
       console.error(error)
       process.exit(1)
@@ -211,7 +223,19 @@ describe('Get Environments Tests', () => {
           }
         )
 
-      expect(environments).toHaveLength(2)
+      expect(environments.items).toHaveLength(2)
+      expect(environments.metadata.totalCount).toEqual(2)
+      expect(environments.metadata.links.self).toBe(
+        `/environment/all/${projectId}?page=0&limit=10&sort=name&order=asc&search=`
+      )
+      expect(environments.metadata.links.first).toBe(
+        `/environment/all/${projectId}?page=0&limit=10&sort=name&order=asc&search=`
+      )
+      expect(environments.metadata.links.previous).toBeNull()
+      expect(environments.metadata.links.next).toBeNull()
+      expect(environments.metadata.links.last).toBe(
+        `/environment/all/${projectId}?page=0&limit=10&sort=name&order=asc&search=`
+      )
     } catch (error) {
       console.error(error)
       process.exit(1)