How to handle element not found exception in Protr

问题:

Just like Selenium webdriver provides various Exception handling for Java, is there any way we can achieve same using Protractor.

If we want to handle element not found exception, then what is the best way to do it using Protractor?

回答1:

Answer to this question is now in Protractor's FAQ

How can I catch errors such as ElementNotFound?

WebDriver throws errors when commands cannot be completed - e.g. not being able to click on an element which is obscured by another element. If you need to retry these actions, try using webdriverjs-retry. If you would just like to catch the error, do so like this

Adapted to your question:

elm.isPresent().then(function(present) {
  /* no webdriver js errors here */}
  if (present) {
    /* element exists */
  } else {
    /* element doesn't exist */
  }
, function(err) {
  /* error handling here, i.e. element doesn't if got ElementNotFound
     but, eventually and less likely, other issues will fall in here too like
     NoSuchWindowsError or ElementStaleError etc...
  */
});

回答2:

Kudos to @Leo Gallucci for his adaptation to the OP's question:

I faced this issue today and was hoping to go for a clean-looking solution like this :

/* Function to check for three possible DOM elements; return the element which exists, and get the text contents. */
this.getMySelector =  function(){
 if (element(by.css('.mySelector')).isPresent()){
   return element(by.css('.mySelector'));
 }
 else if (element(by.css('.mySelector2')).isPresent()){
   return element(by.css('.mySelector2'));
 }
 else{
  return element(by.css('.mySelector3'));
 }
}

however, it was always hitting the first if() and never checking other conditions. Turns out I needed to chain the promises for my scenario:

this.getMySelector =  function(){
    
  element(by.css('.mySelector')).isPresent().then(function (pres) {
    if (pres){
      defer.fulfill(  by.css('.mySelector')).getText() );
    }
    else{
       element(by.css('.mySelector2')).isPresent().then(function (pres) {
         if (pres){
            defer.fulfill(..);
         }
       }
    }
  }
}

// From calling test-spec.js file
getMySelector.then(function(text)){
   console.log('Now I got the text ==> ' + text);         
}
                                                        
                                                       

回答3:

Try, Catch has the following syntax in Protractor. The below code will first find an element by Id 'IdTextBoxCode'. Then the code to enter code 'codeTextBox.sendKeys(code);' is in TRY block. If the code throws exception(in this case, if the element with Id 'IdTextBoxCode' is not found), then it will go to the catch block and the error handling function.

browser.driver.findElement(by.id(browser.params.loginPage.IdTextBoxCode)).then(function(codeTextBox)
    {
        try 
        {
            console.log("Entering Code: "+code);
            codeTextBox.sendKeys(code);
        }
        catch(err) {
            console.log('In catch block');
        }
   }, function(err) {
        console.info('Code Text Box not displayed on page. Proceeding with default Code');
    });