chore: add maxNumProviders option to find providers

src/index.js

@@ -456,6 +456,7 @@ class KadDHT {
    * @param {CID} key
    * @param {Object} options - findProviders options
    * @param {number} options.maxTimeout - how long the query should maximally run, in milliseconds (default: 60000)
+   * @param {number} options.maxNumProviders - maximum number of providers to find
    * @param {function(Error, Array<PeerInfo>)} callback
    * @returns {void}
    */
@@ -471,12 +472,11 @@ class KadDHT {
       options = options || {}
     }
 
-    if (!options.maxTimeout) {
-      options.maxTimeout = c.minute
-    }
+    options.maxTimeout = options.maxTimeout || c.minute
+    options.maxNumProviders = options.maxNumProviders || c.K
 
     this._log('findProviders %s', key.toBaseEncodedString())
-    this._findNProviders(key, options.maxTimeout, c.K, callback)
+    this._findNProviders(key, options.maxTimeout, options.maxNumProviders, callback)
   }
 
   // ----------- Peer Routing

test/kad-dht.spec.js

@@ -342,6 +342,37 @@ describe('KadDHT', () => {
     })
   })
 
+  it('find providers', function (done) {
+    this.timeout(20 * 1000)
+
+    const val = values[0]
+    const tdht = new TestDHT()
+
+    tdht.spawn(3, (err, dhts) => {
+      expect(err).to.not.exist()
+
+      series([
+        (cb) => connect(dhts[0], dhts[1], cb),
+        (cb) => connect(dhts[1], dhts[2], cb),
+        (cb) => each(dhts, (dht, cb) => dht.provide(val.cid, cb), cb),
+        (cb) => dhts[0].findProviders(val.cid, {}, cb),
+        (cb) => dhts[0].findProviders(val.cid, { maxNumProviders: 2 }, cb)
+      ], (err, res) => {
+        expect(err).to.not.exist()
+
+        // find providers find all the 3 providers
+        expect(res[3]).to.exist()
+        expect(res[3]).to.have.length(3)
+
+        // find providers limited to a maxium of 2 providers
+        expect(res[4]).to.exist()
+        expect(res[4]).to.have.length(2)
+
+        done()
+      })
+    })
+  })
+
   it('random-walk', function (done) {
     this.timeout(40 * 1000)