How to create webdriver.io custom function?

Question

I'm using webdriver.io with mocha.js and I need to create some action for many times, and I dont want to duplicate my code, so I want to create custom function and call to the function in each mocha test (it)...

for an example:

    describe('Register', function () {
      it('Login', function (done) {
         client
          .url('http://exmaple.site.com)
          .setValue('input[name="username"]', login.username)
          .setValue('input[name="password"]', login.password)
          .call(done);
      }

      it('Login and logout', function (done) {
         client
          .url('http://exmaple.site.com)
          .setValue('input[name="username"]', login.username)
          .setValue('input[name="password"]', login.password)
          .click('#logout')
          .call(done);
      }
    }

So like you can see here Im duplicate my login codes...

There is any way to create function like login and call it in the test (it):

function login(){
   client
   .setValue('input[name="username"]', login.username)
   .setValue('input[name="password"]', login.password)
}

thanks.

Answer 1

I'm not really sure what your intentions with the login/logout, but here's a generic custom command, webdriver.io custom command

client.addCommand('goGetTitle', function() {

    return client
        .url('https://www.yahoo.com/')
        .getTitle()

});

describe('Test', function() {
    it('should have gotten the title', function(done) {

        client.goGetTitle().then(function(title) {
                console.log('title', title);
            })
            .call(done);
    });
});

Answer 2

try this

function login(){
  return client
  .setValue('input[name="username"]', login.username)
  .setValue('input[name="password"]', login.password)
}

describe('Register', function () {
  it('Login', function (done) {
     client
      .url('http://exmaple.site.com)
      .then( login )
      .call(done);
  }

  it('Login and logout', function (done) {
     client
      .url('http://exmaple.site.com)
      .then(login)
      .click('#logout')
      .call(done);
  }
}

basically you will replace your repeated login by .then(login). Because login returning client promise, everything works as excepted.