Add fee estimation functions for dogecoin and litecoin

src/networks.js

@@ -1,10 +1,6 @@
 // https://en.bitcoin.it/wiki/List_of_address_prefixes
 // Dogecoin BIP32 is a proposed standard: https://bitcointalk.org/index.php?topic=409731
 
-function bitcoinEstimateFee(txByteSize) {
-  return networks.bitcoin.feePerKb * Math.ceil(txByteSize / 1000)
-}
-
 var networks = {
   bitcoin: {
     magicPrefix: '\x18Bitcoin Signed Message:\n',
@@ -15,9 +11,9 @@ var networks = {
     pubKeyHash: 0x00,
     scriptHash: 0x05,
     wif: 0x80,
-    dustThreshold: 546, // https://github.com/bitcoin/bitcoin/blob/529047fcd18acd1b64dc95d6eb69edeaad75d405/src/core.h#L176-L188
-    feePerKb: 10000, // https://github.com/bitcoin/bitcoin/blob/3f39b9d4551d729c3a2e4decd810ac6887cfaeb3/src/main.cpp#L52
-    estimateFee: bitcoinEstimateFee
+    dustThreshold: 546,
+    feePerKb: 10000,
+    estimateFee: estimateFee('bitcoin')
   },
   dogecoin: {
     magicPrefix: '\x19Dogecoin Signed Message:\n',
@@ -29,7 +25,9 @@ var networks = {
     scriptHash: 0x16,
     wif: 0x9e,
     dustThreshold: 0,
-    feePerKb: 100000000
+    dustSoftThreshold: 100000000,
+    feePerKb: 100000000,
+    estimateFee: estimateFee('dogecoin')
   },
   litecoin: {
     magicPrefix: '\x19Litecoin Signed Message:\n',
@@ -41,7 +39,9 @@ var networks = {
     scriptHash: 0x05,
     wif: 0xb0,
     dustThreshold: 0,
-    feePerKb: 100000
+    dustSoftThreshold: 100000,
+    feePerKb: 100000,
+    estimateFee: estimateFee('litecoin')
   },
   testnet: {
     magicPrefix: '\x18Bitcoin Signed Message:\n',
@@ -54,7 +54,27 @@ var networks = {
     wif: 0xef,
     dustThreshold: 546,
     feePerKb: 10000,
-    estimateFee: bitcoinEstimateFee
+    estimateFee: estimateFee('bitcoin')
   }
 }
+
+function estimateFee(type) {
+  return function(tx) {
+    var network = networks[type]
+    var baseFee = network.feePerKb
+    var byteSize = tx.toBuffer().length
+
+    var fee = baseFee * Math.ceil(byteSize / 1000)
+    if(network.dustSoftThreshold == undefined) return fee
+
+    tx.outs.forEach(function(e){
+      if(e.value < network.dustSoftThreshold) {
+        fee += baseFee
+      }
+    })
+
+    return fee
+  }
+}
+
 module.exports = networks

src/wallet.js

@@ -236,8 +236,7 @@ function Wallet(seed, network) {
     var tmpTx = tx.clone()
     tmpTx.addOutput(getChangeAddress(), 0)
 
-    var byteSize = tmpTx.toBuffer().length
-    return network.estimateFee(byteSize)
+    return network.estimateFee(tmpTx)
   }
 
   function getChangeAddress() {

test/network.js

@@ -6,18 +6,84 @@ var fixtureTxes = require('./fixtures/mainnet_tx')
 var fixtureTx1Hex = fixtureTxes.prevTx
 var fixtureTxBigHex = fixtureTxes.bigTx
 
-describe('bitcoin', function() {
-  describe('estimateFee', function() {
-    var estimateFee = networks.bitcoin.estimateFee
+describe('networks', function() {
+  describe('bitcoin', function() {
+    describe('estimateFee', function() {
+      var estimateFee = networks.bitcoin.estimateFee
 
-    it('works for fixture tx 1', function() {
-      var tx = Transaction.fromHex(fixtureTx1Hex)
-      assert.equal(estimateFee(tx.toBuffer().length), 10000)
+      it('works for fixture tx 1', function() {
+        var tx = Transaction.fromHex(fixtureTx1Hex)
+        assert.equal(estimateFee(tx), 10000)
+      })
+
+      it('works for fixture big tx', function() {
+        var tx = Transaction.fromHex(fixtureTxBigHex)
+        assert.equal(estimateFee(tx), 30000)
+      })
     })
+  })
 
-    it('works for fixture big tx', function() {
-      var tx = Transaction.fromHex(fixtureTxBigHex)
-      assert.equal(estimateFee(tx.toBuffer().length), 30000)
+  describe('dogecoin', function() {
+    describe('estimateFee', function() {
+      var estimateFee = networks.dogecoin.estimateFee
+
+      it('regular fee per kb applies when every output has value no less than DUST_SOFT_LIMIT', function() {
+        var tx = Transaction.fromHex(fixtureTx1Hex)
+        tx.outs.forEach(function(e){
+          e.value = 100000000
+        })
+
+        assert.equal(estimateFee(tx), 100000000)
+      })
+
+      it('applies additional fee on every output with value below DUST_SOFT_LIMIT', function() {
+        var tx = Transaction.fromHex(fixtureTx1Hex)
+        tx.outs.forEach(function(e){
+          e.value = 99999999
+        })
+
+        assert.equal(estimateFee(tx), 4 * 100000000) // 3 outs in total
+      })
+
+      it('works for fixture big tx', function() {
+        var tx = Transaction.fromHex(fixtureTxBigHex)
+        tx.outs.forEach(function(e){
+          e.value = 100000000
+        })
+        assert.equal(estimateFee(tx), 300000000)
+      })
+    })
+  })
+
+  describe('litecoin', function() {
+    describe('estimateFee', function() {
+      var estimateFee = networks.litecoin.estimateFee
+
+      it('regular fee per kb applies when every output has value no less than DUST_SOFT_LIMIT', function() {
+        var tx = Transaction.fromHex(fixtureTx1Hex)
+        tx.outs.forEach(function(e){
+          e.value = 100000
+        })
+
+        assert.equal(estimateFee(tx), 100000)
+      })
+
+      it('applies additional fee on every output with value below DUST_SOFT_LIMIT', function() {
+        var tx = Transaction.fromHex(fixtureTx1Hex)
+        tx.outs.forEach(function(e){
+          e.value = 99999
+        })
+
+        assert.equal(estimateFee(tx), 4 * 100000) // 3 outs in total
+      })
+
+      it('works for fixture big tx', function() {
+        var tx = Transaction.fromHex(fixtureTxBigHex)
+        tx.outs.forEach(function(e){
+          e.value = 100000
+        })
+        assert.equal(estimateFee(tx), 300000)
+      })
     })
   })
 })