Merge pull request #96 from 67P/feature/pagination

Add pagination for .all methods

lib/contracts/contribution.js

@@ -1,21 +1,9 @@
-const ethers = require('ethers');
-
+const Record = require('./record');
 const ContributionSerializer = require('../serializers/contribution');
-const Base = require('./base');
 
-class Contribution extends Base {
-  all() {
-    return this.functions.contributionsCount()
-      .then(async (count) => {
-        let contributions = [];
-
-        for (let id = 1; id <= count; id++) {
-          const contribution = await this.getById(id)
-          contributions.push(contribution);
-        }
-
-        return contributions;
-      });
+class Contribution extends Record {
+  get count () {
+    return this.functions.contributionsCount();
   }
 
   getById(id) {

lib/contracts/contributor.js

@@ -1,20 +1,9 @@
-const RSVP = require('rsvp');
-
+const Record = require('./record');
 const ContributorSerializer = require('../serializers/contributor');
-const Base = require('./base');
 
-class Contributor extends Base {
-  all() {
-    return this.functions.contributorsCount()
-      .then(count => {
-        let contributors = [];
-
-        for (let id = 1; id <= count; id++) {
-          contributors.push(this.getById(id));
-        }
-
-        return RSVP.all(contributors);
-      });
+class Contributor extends Record {
+  get count () {
+    return this.functions.contributorsCount();
   }
 
   getById(id) {

lib/contracts/proposal.js

@@ -1,20 +1,9 @@
-const RSVP = require('rsvp');
-
+const Record = require('./record');
 const ContributionSerializer = require('../serializers/contribution');
-const Base = require('./base');
 
-class Proposal extends Base {
-  all() {
-    return this.functions.proposalsCount()
-      .then(count => {
-        let proposals = [];
-
-        for (let id = 1; id <= count; id++) {
-          proposals.push(this.getById(id));
-        }
-
-        return RSVP.all(proposals);
-      });
+class Proposal extends Record {
+  get count () {
+    return this.functions.proposalsCount();
   }
 
   getById(id) {

lib/contracts/record.js

@@ -0,0 +1,14 @@
+const Base = require('./base');
+const paged = require('../utils/pagination');
+
+class Record extends Base {
+  all(options = {}) {
+    return this.count
+      .then((count) => {
+        let records = paged(count, options).map((id) => this.getById(id));
+        return Promise.all(records);
+      });
+  }
+}
+
+module.exports = Record

lib/kredits.js

@@ -1,5 +1,4 @@
 const ethers = require('ethers');
-const RSVP = require('rsvp');
 
 const Preflight = require('./utils/preflight');
 
@@ -57,7 +56,8 @@ class Kredits {
           );
         });
       });
-      return RSVP.all(addressPromises).then(() => { return this });
+
+      return Promise.all(addressPromises).then(() => { return this });
     });
   }
 

lib/utils/pagination.js

@@ -0,0 +1,46 @@
+function pageNumber(number, size, recordCount) {
+  let numberOfPages = Math.ceil(recordCount / size);
+
+  number = parseInt(number) || 1;
+
+  // Ensure page number is in range
+  number = number < 1 ? 1 : number;
+  number = number > numberOfPages ? numberOfPages : number;
+
+  return number;
+}
+
+function buildIds(order, number, size, recordCount) {
+  let offset = size * (number - 1);
+
+  let start;
+  let mapFunction;
+
+  if (order === 'asc') {
+    start = 1 + offset;
+    mapFunction = (_, i) => start + i;
+  } else {
+    start = recordCount - offset;
+    mapFunction = (_, i) => start - i;
+  }
+
+  // Ensure size is in range
+  let end = offset + size;
+  if (end > recordCount) {
+    let diff = end - recordCount;
+    size = size - diff;
+  }
+
+  return Array.from({ length: size }, mapFunction);
+}
+
+module.exports = function paged(recordCount, options = {}) {
+  let { order, page } = options;
+  order = order || 'desc';
+  page = page || {};
+
+  let size = parseInt(page.size) || 25;
+  let number = pageNumber(page.number, size, recordCount);
+
+  return buildIds(order, number, size, recordCount);
+};

package.json

@@ -46,7 +46,6 @@
     "ethers": "^4.0.27",
     "ipfs-http-client": "^30.1.1",
     "kosmos-schemas": "^2.0.0",
-    "rsvp": "^4.8.2",
     "tv4": "^1.3.0"
   },
   "keywords": [