Merge pull request #18 from openearth/feat/DGDS-96--see-all-locations

Feat/dgds 96  see all locations

.eslintrc.prod.js

@@ -4,8 +4,8 @@ const baseConfig = require('./.eslintrc.js')
 const prodRules = {
   rules: {
     'no-console': 'error',
-    'no-unused-vars': 'error'
-  }
+    'no-unused-vars': 'error',
+  },
 }
 
 module.exports = merge(baseConfig, prodRules)

.gitignore

@@ -82,3 +82,6 @@ dist
 
 # Service worker
 sw.*
+
+# Git templates
+.gitmessage

api-mock/redirect-middleware.js

@@ -1,8 +1,16 @@
+const path = require('path')
+
 module.exports = function(req, res, next) {
   if (req.path === '/timeseries') {
     res.redirect(`${req.path}/${req.query.locationCode}/${req.query.datasetId}`)
   } else if (req.path === '/locations') {
-    res.redirect(`${req.path}/${req.query.datasetId}`)
+    const paginated = req.query.page ? `-page=${req.query.page}` : '-page=1'
+    res.sendFile(
+      path.join(
+        __dirname,
+        `${req.path}/${req.query.datasetId}${paginated}.json`,
+      ),
+    )
   } else {
     next()
   }

lib/load-locations.js

@@ -0,0 +1,86 @@
+import times from 'lodash/fp/times'
+import pipe from 'lodash/fp/pipe'
+import get from 'lodash/fp/get'
+import map from 'lodash/fp/map'
+import flatten from 'lodash/fp/flatten'
+import identity from 'lodash/fp/identity'
+import getFromApi from './request/get'
+
+const delay = ms => new Promise(resolve => setTimeout(_ => resolve(), ms))
+const plus = a => b => a + b
+const plusOne = plus(1)
+
+const load = parameters => _page => {
+  const page = _page > 1 ? { page: _page } : {}
+  return getFromApi('locations', { ...parameters, ...page })
+}
+
+// prettier-ignore
+const batch = size => arr =>
+  arr.reduce((list, item, index) => {
+    const listLastIndex = Math.max(list.length - 1, 0)
+
+    index % size
+      ? list[listLastIndex].push(item)
+      : list.push([item])
+
+    return list
+  }, [])
+
+/**
+ * Calls a callback with the results object from the locations endpoint
+ *
+ * @param {Object} parameters Parameters for the get request
+ * @param {Function} callback The callback to be called with the results
+ */
+export default async function loadLocations(parameters, callback) {
+  const loadPage = load(parameters)
+  const firstPageResponse = await loadPage(1)
+  const { paging, results } = firstPageResponse
+  const { totalObjectCount } = paging
+  const resultLength = results.length
+  const totalPages = Math.ceil(totalObjectCount / resultLength)
+  const totalAdditionalPages = totalPages - 1
+  const handleResponse = pipe([get('results'), callback])
+
+  const loadAdditionalPages = ({
+    offset,
+    batchSize,
+    totalPages,
+    callback,
+    delayPerBatch,
+  }) =>
+    pipe([
+      times(identity),
+      map(plusOne),
+      map(plus(offset)),
+      batch(batchSize),
+      map(arr => fn => Promise.all(arr.map(fn))),
+      loadBatchesSequential({ callback, delayPerBatch }),
+    ])(totalPages)
+
+  const loadBatchesSequential = ({ callback, delayPerBatch }) => batches => {
+    return new Promise(async (resolve, reject) => {
+      let results = []
+      for (const batch of batches) {
+        await delay(delayPerBatch)
+        const responses = await batch(loadPage)
+        results = [...results, ...responses.map(callback)]
+      }
+      resolve(results)
+    })
+  }
+
+  const promises = [
+    Promise.resolve([handleResponse(firstPageResponse)]),
+    loadAdditionalPages({
+      callback: handleResponse,
+      offset: 1,
+      batchSize: 10,
+      delayPerBatch: 500,
+      totalPages: totalAdditionalPages,
+    }),
+  ]
+
+  return Promise.all(promises).then(flatten)
+}

lib/utils.js

@@ -1,6 +1,7 @@
 import includes from 'lodash/includes'
 import get from 'lodash/get'
 import curry from 'lodash/curry'
+import clone from 'lodash/clone'
 import filter from 'lodash/filter'
 import matches from 'lodash/matches'
 import moment from 'moment'
@@ -110,3 +111,27 @@ export const mapAsync = curry((fn, items) => Promise.all(items.map(fn)))
 export const filterBy = curry((source, collection) =>
   filter(collection, matches(source)),
 )
+
+/**
+ * Clones an object and return it frozen
+ *
+ * @param {Object} object The object to freeze
+ *
+ * @example
+ * const a = {b: 1}
+ * freeze(a) // Returns a frozen clone of a
+ */
+export const freeze = object => Object.freeze(clone(object))
+
+/**
+ * Executes the then method with the provided callback on a promise
+ *
+ * @param {Function} callback The callback to execute once the promise resolves
+ * @param {Promise} promise The promise to resolve
+ *
+ * @example
+ * const promise = Promise.resolve('foo')
+ * const log = console.log
+ * then(log, promise) // "foo"
+ */
+export const then = curry((callback, promise) => promise.then(callback))