GC endpoint (#992)

* feat: gc

* fix: better repo.gc() response handling

* fix: repo.gc() cid handling

* chore: update interface-ipfs-core

package.json

@@ -85,7 +85,7 @@
     "cross-env": "^5.2.0",
     "dirty-chai": "^2.0.1",
     "go-ipfs-dep": "~0.4.21",
-    "interface-ipfs-core": "~0.105.0",
+    "interface-ipfs-core": "~0.106.0",
     "ipfsd-ctl": "~0.43.0",
     "nock": "^10.0.2",
     "stream-equal": "^1.1.1"

src/repo/gc.js

@@ -1,16 +1,33 @@
 'use strict'
 
 const promisify = require('promisify-es6')
+const streamToValueWithTransformer = require('../utils/stream-to-value-with-transformer')
+const CID = require('cids')
+
+const transform = function (res, callback) {
+  callback(null, res.map(r => ({
+    err: r.Err ? new Error(r.Err) : null,
+    cid: (r.Key || {})['/'] ? new CID(r.Key['/']) : null
+  })))
+}
 
 module.exports = (send) => {
   return promisify((opts, callback) => {
     if (typeof (opts) === 'function') {
       callback = opts
       opts = {}
     }
-    send({
+
+    const request = {
       path: 'repo/gc',
       qs: opts
-    }, callback)
+    }
+    send(request, (err, result) => {
+      if (err) {
+        return callback(err)
+      }
+
+      streamToValueWithTransformer(result, transform, callback)
+    })
   })
 }