implement pagination using skip & limit

lib/server.js

@@ -913,12 +913,11 @@ WalletService.prototype._normalizeTxHistory = function(txs) {
 };
 
 /**
- * Retrieves all transactions (incoming & outgoing) in the range (maxTs-minTs)
+ * Retrieves all transactions (incoming & outgoing)
  * Times are in UNIX EPOCH
  *
  * @param {Object} opts
- * @param {Number} opts.minTs (defaults to 0)
- * @param {Number} opts.maxTs (defaults to now)
+ * @param {Number} opts.skip (defaults to 0)
  * @param {Number} opts.limit
  * @returns {TxProposal[]} Transaction proposals, first newer
  */
@@ -1003,17 +1002,14 @@ WalletService.prototype.getTxHistory = function(opts, cb) {
   };
 
   function paginate(txs) {
-    var limited = opts.limit && opts.limit != -1;
-    var minTs = opts.minTs || 0;
-    var maxTs = opts.maxTs || Math.ceil(Date.now() / 1000);
+    var skip = opts.skip || 0;
+    var limited = _.isNumber(opts.limit) && opts.limit != -1;
 
-    var filtered = _.sortBy(_.filter(txs, function(tx) {
-      return tx.time >= minTs && tx.time <= maxTs;
-    }), function(tx) {
+    var sliced = _.slice(_.sortBy(txs, function(tx) {
       return -tx.time;
-    });
+    }), skip);
 
-    return limited ? _.take(filtered, opts.limit) : filtered;
+    return limited ? _.take(sliced, opts.limit) : sliced;
   };
 
   // Get addresses for this wallet

test/integration/server.js

@@ -2383,6 +2383,18 @@ describe('Copay server', function() {
           limit: 0,
         },
         expected: [],
+      }, {
+        opts: {
+          skip: 4,
+          limit: 20,
+        },
+        expected: [10],
+      }, {
+        opts: {
+          skip: 20,
+          limit: 1,
+        },
+        expected: [],
       }];
 
       server._normalizeTxHistory = sinon.stub().returnsArg(0);