Merge 28c352b into abf3fd7

README.md

@@ -91,6 +91,11 @@ The query object will look like this, for a request for items of type `entry`:
 }
 ```
 
+When the `pageSize` param is set in a request, it is taken as the max number of
+documents to return in the response. When nothing else is specified, the first
+page of documents is returned, and the `paging.next` prop on the response will
+hold a params object that may be used to get the next page.
+
 **Note 1:** This adapter is currently updating and deleting arrays of documents
 by calling `updateOne` and `deleteOne` for every item in the array. This is not
 the best method of doing it, so stay tuned for improvements.

lib/adapter/createPaging-test.js

@@ -0,0 +1,143 @@
+import test from 'ava'
+
+import createPaging from './createPaging'
+
+// Helpers
+
+const prepareData = (data) => data.map((item) => ({...item, _id: `${item.type}:${item.id}`}))
+
+// Tests
+
+test('should return next: null when no data', (t) => {
+  const data = []
+  const params = {type: 'entry', pageSize: 2}
+  const expected = {next: null}
+
+  const ret = createPaging(data, params)
+
+  t.deepEqual(ret, expected)
+})
+
+test('should return paging for first page', (t) => {
+  const data = prepareData([{id: 'ent1', type: 'entry'}, {id: 'ent2', type: 'entry'}])
+  const params = {
+    type: 'entry',
+    pageSize: 2
+  }
+  const expected = {
+    next: {
+      type: 'entry',
+      query: {_id: {$gte: 'entry:ent2'}},
+      pageAfter: 'entry:ent2',
+      pageSize: 2
+    }
+  }
+
+  const ret = createPaging(data, params)
+
+  t.deepEqual(ret, expected)
+})
+
+test('should return paging for second page', (t) => {
+  const data = prepareData([{id: 'ent3', type: 'entry'}, {id: 'ent4', type: 'entry'}])
+  const params = {
+    type: 'entry',
+    query: {_id: {$gte: 'entry:ent2'}},
+    pageAfter: 'entry:ent2',
+    pageSize: 2
+  }
+  const expected = {
+    next: {
+      type: 'entry',
+      query: {_id: {$gte: 'entry:ent4'}},
+      pageAfter: 'entry:ent4',
+      pageSize: 2
+    }
+  }
+
+  const ret = createPaging(data, params)
+
+  t.deepEqual(ret, expected)
+})
+
+test('should return paging when sorting', (t) => {
+  const data = prepareData([
+    {id: 'ent2', type: 'entry', attributes: {index: 1}},
+    {id: 'ent3', type: 'entry', attributes: {index: 2}}
+  ])
+  const params = {
+    type: 'entry',
+    pageSize: 2
+  }
+  const sort = {
+    'attributes.index': 1
+  }
+  const expected = {
+    next: {
+      type: 'entry',
+      query: {'attributes.index': {$gte: 2}},
+      pageAfter: 'entry:ent3',
+      pageSize: 2
+    }
+  }
+
+  const ret = createPaging(data, params, sort)
+
+  t.deepEqual(ret, expected)
+})
+
+test('should return paging when sorting descending', (t) => {
+  const data = prepareData([
+    {id: 'ent3', type: 'entry', attributes: {index: 2}},
+    {id: 'ent2', type: 'entry', attributes: {index: 1}}
+  ])
+  const params = {
+    type: 'entry',
+    pageSize: 2
+  }
+  const sort = {
+    'attributes.index': -1
+  }
+  const expected = {
+    next: {
+      type: 'entry',
+      query: {'attributes.index': {$lte: 1}},
+      pageAfter: 'entry:ent2',
+      pageSize: 2
+    }
+  }
+
+  const ret = createPaging(data, params, sort)
+
+  t.deepEqual(ret, expected)
+})
+
+test('should return paging when sorting ascending and descending', (t) => {
+  const data = prepareData([
+    {id: 'ent3', type: 'entry', attributes: {index: 2}},
+    {id: 'ent2', type: 'entry', attributes: {index: 1}}
+  ])
+  const params = {
+    type: 'entry',
+    pageSize: 2
+  }
+  const sort = {
+    'attributes.index': -1,
+    id: 1
+  }
+  const expected = {
+    next: {
+      type: 'entry',
+      query: {
+        'attributes.index': {$lte: 1},
+        id: {$gte: 'ent2'}
+      },
+      pageAfter: 'entry:ent2',
+      pageSize: 2
+    }
+  }
+
+  const ret = createPaging(data, params, sort)
+
+  t.deepEqual(ret, expected)
+})

lib/adapter/createPaging.js

@@ -0,0 +1,35 @@
+const dotprop = require('dot-prop')
+
+const createQuery = (lastItem, sort) => {
+  if (sort) {
+    return Object.keys(sort).reduce((query, key) => {
+      const value = dotprop.get(lastItem, key)
+      const operator = (sort[key] > 0) ? '$gte' : '$lte'
+      return {...query, [key]: {[operator]: value}}
+    }, {})
+  } else {
+    return {_id: {$gte: lastItem._id}}
+  }
+}
+
+const createPaging = (data, params, sort) => {
+  if (data.length === 0) {
+    return {next: null}
+  }
+  const lastItem = data[data.length - 1]
+
+  const {typePlural, ...nextParams} = params
+
+  const query = createQuery(lastItem, sort)
+
+  return {
+    next: {
+      ...nextParams,
+      pageSize: params.pageSize,
+      pageAfter: lastItem._id,
+      query
+    }
+  }
+}
+
+module.exports = createPaging