inject function improvements

[pvdlg]

This PR provide 2 improvements to the inject function:

• Allow to define multiple answer for the same question, which allow to support repeated questions
• Trigger all the callback that a non inject answer would which allow to test functionalities such as onSubmit or format

Here is an example of a prompt and it's associated test:

const prompts = require('prompts');
const delay = require('delay');

const questions = [{
    type: 'number',
    name: 'price',
    message: 'Guess the price',
    format: val => Intl.NumberFormat(undefined, { style: 'currency', currency: 'USD' }).format(val)
}];
const answers = [];

const ask = async questions => prompts(questions, {
   onSubmit: async (prompt, response) => {
    if (prompt.name === 'price' && !(await checkPriceOnServer(response))) {
      console.log('You guessed wrong...try again!');
      // Ask again and collect answer
      answers.push(await ask(questions));
      return;
    }
    console.log('You guessed right!');
  },
    onCancel: async prompt => {
      if (prompt.name === 'price') {
        console.log('Don\'t stop prompting until you guess right...');
        // Ask again and collect answer
        answers.push(await ask(questions));
        return true;
      }
    }
})

async function checkPriceOnServer(price) {
  // Simulate async response
  return delay(1000).then(() => price === '$10.00');
}

module.exports = async () => {
  await ask(questions);
  return Object.assign(...answers.reverse());
};

const prompts = require('prompts');
const prompter = require('./prompter');
prompts.inject({price: [5, new Error('Hit Ctrl+C'), 10]});
prompter().then(console.log);

// => You guessed wrong...try again!
// => Don't stop prompting until you guess right...
// => You guessed right!
// => { price: '$10.00' }

[terkelg]

Thanks @pvdlg! I'll take a look at this over the weekend. Looks good

[terkelg]

Looks good to me. What do you think @lukeed?

[lukeed]

Hmm.. wouldn't this break/change the responses to select and multiselect prompts? Those should be Arrays, and if I'm not mistaken, this PR will treat all Arrays as a list to cycle through, rather than accepting it's answer in array-form.

[pvdlg]

Yes indeed that would be problematic for multiselect as we would have no way to tell if an Array is a single answer with multiple values or multiple answers with a single value.

The objective was to not make a breaking change, but I overlooked that particular case.
As it seems a breaking change is inevitable, maybe we could change the API to accept only an Array of answers.

prompts.inject(['answer1', ['multiple', 'multiselect', 'answers'], 'answer3']);

Or do you have a preference for a different API?

[lukeed]

Sure, that could work! A lot of (deep) nested arrays can be visually confusing though, so we may want to explore a second parameter that toggles an iterate key that, when true, either rights into a second object or configures the same object with a specialty so that at runtime we know if we are iterating or using an arra value. That way we can iterate through any type of prompt

[pvdlg]

That would be only one level of nested array, so not that deep.

I don't really understand what you are suggesting...Can you provide an example of how that API would be used?

[terkelg]

Sorry I'm not to much help here. @lukeed can you elaborate for @pvdlg?

[lukeed]

Oh, sorry~! I typed that on the run, hence no code sample.

I think I meant this:

// Instead of:

prompts.inject({
  text: 'foo', // regular
  age: [5, new Error('Hit Ctrl+C'), 10], // must iterate
  choice: [['one', 'two']], // this should be Array-type answer
  confirm: true
]);

// Do this:

prompts.inject({
  text: 'foo', // regular
  choice: ['one', 'two'], // regular Array-type answer
  confirm: true
});

prompts.inject({
  age: [5, new Error('Hit Ctrl+C'), 10], // must iterate
}, true); //=> true == must iterate

Doesn't really matter to me – as @pvdlg pointed out, it's only one extra level of depth/nesting, so that's not a big deal. This was just an idea

[hasahmed]

Needing this functionality. Specifically to run the format callbacks when injections are used for testing. I went ahead and forked @pvdlg to use these changes, but I would like to be back to the main repo if possible.

[terkelg]

Sorry, I've been busy. @pvdlg is this ready for merge?

[pvdlg]

@terkelg it depends. I tried to avoid making a breaking change, but as @lukeed mentioned there is a case where is a breaking change (multiselect prompts).

So if we are ok with a breaking change we might simplify the API further. Instead of passing objects with the prompt type and the values we want we could just pass a list of value without having to specify the prompt type.

For example with:

prompts.inject(['abc', ['item1', 'item2', 'item3'], 10]);

The fist prompt would receive 'abc', the second one ['item1', 'item2', 'item3'] and the third one 10. That would be independent of the prompt type.

It would up to the user to determine what prompt their test is supposed to call and inject the mock data accordingly.

I think this solution is more simple both in terms of implementation and clarity for the end user, as specify the prompt id doesn't serve much purpose in the context of tests.

Let me know if you'd like to make those changes.

[terkelg]

@pvdlg agree! Breaking changes are fine - let's keep it simple

[pvdlg]

@terkelg ok I updated the PR accordingly

[terkelg]

Thank you so much @pvdlg