I have two functions,

One that returns web.eth.sendTransaction, which triggers metamask a first time,

And one that returns contractInstance.function that updates an array in my contract. Which also triggers metamask.

Both are in the same big function in my app.js,

I would like obtain the same result, which is receive a payment, and then update the book in the contract, by only calling metamask once.

What is the best practice?

markAdopted: function(adopters, account) {
    var adoptionInstance;

    App.contracts.Adoption.deployed().then(function(instance) {
      adoptionInstance = instance;

      return adoptionInstance.getAdopters.call();
    }).then(function(adopters) {
      for (i = 0; i < adopters.length; i++) {
        if (adopters[i] !== '0x0000000000000000000000000000000000000000') {
          $('.panel-pet').eq(i).find('button').text('Coped').attr('disabled', true);
    }).catch(function(err) {

  handleAdopt: function(event) {

    var petId = parseInt($(event.target).data('id'));
    var adoptionInstance;
    var account;
    var transactionStatus;

    web3.eth.getAccounts(function(error, accounts) {
      if (error) {

      account = accounts[0];


      from: account,
      to: '0xC5fdf4076b8F3A5357c5E395ab970B5B54098Fef',
      value: '1000000000000000000'
    }, function(error, result){
    if(!error) {
        transactionStatus = true;
        if (transactionStatus) {
        App.contracts.Adoption.deployed().then(function(instance) {

        adoptionInstance = instance;

        return adoptionInstance.adopt(petId, {from: account});

      }).then(function(result) {

        return App.markAdopted();
      }).catch(function(err) {


    else {
        transactionStatus = false;


Unless you are willing to make that update array function a payable and merge the code, you are essentially requesting 2 actions to be completed which will require 2 triggers.

An alternative is you connect a medium account, securely on the backend, to connect and trigger the second call through...Unfortunately, you will also incur the gas cost.

Best bet is to try to re-think how the contract is programmed and try to do more with fewer function calls.

| improve this answer | |
  • How would the fact that I do a payable function will lead me to have only one call ? I do not mind having a payable function. I thought about the medium account, I do not mind bearing the gas cost. If you have some more lead on this? I mean I would gladly explore both options. – Ilan Feb 5 '18 at 17:53
  • @Ilan Is your sendTransaction acutally sending data through the optional data parameter? I recommend you show us the code for the transaction itself. – ReyHaynes Feb 5 '18 at 18:33
  • Can I show it in private ? – Ilan Feb 5 '18 at 19:32
  • 1
    @Ilan I would just put it here so you can get the maximum response. Unless you're making something revolutionary, it's pretty safe to put the code you need help with here. – ReyHaynes Feb 5 '18 at 20:47
  • I added the code, in fact it is not revolutionary its just an adapted code from a tutorial – Ilan Feb 5 '18 at 21:01

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