Continue Contribution contract and JS wrapper

lib/contracts/contribution.js

@@ -0,0 +1,51 @@
+const ethers = require('ethers');
+const RSVP = require('rsvp');
+
+const ContributionSerializer = require('../serializers/contribution');
+const Base = require('./base');
+
+class Contribution extends Base {
+  all() {
+    return this.functions.contributionsCount()
+      .then((count) => {
+        count = count.toNumber();
+        let contributions = [];
+
+        for (let id = 1; id <= count; id++) {
+          contributions.push(this.getById(id));
+        }
+
+        return RSVP.all(contributions);
+      });
+  }
+
+  getById(id) {
+    id = ethers.utils.bigNumberify(id);
+
+    return this.functions.getContribution(id)
+      .then((data) => {
+        return this.ipfs.catAndMerge(data, ContributionSerializer.deserialize);
+      });
+
+  }
+
+  getByContributor(contributor) {
+    return this.functions.balanceOf(contributor)
+      then((balance) => {
+        count = balance.toNumber();
+
+        let contributions = [];
+
+        for (let index = 0; index <= count; index++) {
+          this.functions.tokenOfOwnerByIndex(contributor, index)
+            .then((id) => {
+              contributions.push(this.getById(id));
+            });
+        }
+
+        return RSVP.all(contributions);
+      });
+  }
+}
+
+module.exports = Contribution;

lib/contracts/index.js

@@ -1,5 +1,6 @@
 module.exports = {
   Contributors: require('./contributor'),
+  Contribution: require('./contribution'),
   Operator: require('./operator'),
   Token: require('./token'),
   Registry: require('./registry')