code: function mergeTxs(into, from) {
    from.forEach(function(b) {
      var merged = into.some(function(a) {
        if (a.txId === b.txId) {
          if (!equal(a, b)) {
            for (var p in b) {
              a[p] = b[p]
            }
          }
  
          return true
        }
      })
  
      if (!merged) into.push(b)
    })
  }
docs: TODO: optimize