Allow questions to set defaults from previously answered questions in the same set of questions

[rdmulford]

When defining multiple questions in one block, it would be great if you could set the default value for one question equal to the answer of a previously answered question. See example below for more clarity on the issue.

Environments Tested

OS: MacOS Terminal: iTerm2 Shell: zsh Version: github.com/AlecAivazis/survey/v2 v2.0.7

Example Program:

package main

import (
    "github.com/AlecAivazis/survey/v2"
)

type Answers struct {
    Text      string
    Default   string
}

func main() {
    answers := Answers{}
    var questions = []*survey.Question{
        {
            Name:     "Default",
            Prompt:   &survey.Input{Message: "Enter text"},
            Validate: survey.Required,
        },
        {
            Name:     "Default",
            Prompt:   &survey.Input{
                Message: "Enter text (should be default here)",
                Default: answers.Default,
            },
            Validate: survey.Required,
        },
    }
    if err := survey.Ask(questions, &answers); err != nil {
        panic(err)
    }
}

Output

Expected

I would expect the second question to display a default value of text.

[kke]

I think if answers already has a valid value for the key, asking for one should be skipped.

Something like this should go straight through without any prompts, the name should become titlecased.

    name := "hello world"
    email := "hello@example.com"

    userConfig := config.UserConfig{
        Name:    name,
        Email:   email,
    }

    questions := []*survey.Question{
        {
            Name:      "name",
            Prompt:    &survey.Input{Message: "Name"},
            Validate:  validateName,
            Transform: survey.Title,
        },
        {
            Name:     "email",
            Prompt:   &survey.Input{Message: "Email"},
            Validate: validateEmail,
        },
    }
    err := survey.Ask(questions, &userConfig)

[infalmo]

I think if answers already has a valid value for the key, asking for one should be skipped.

Define valid value. nil, 0, "" are all valid values in golang.

[joerodrig]

I stumbled across this case earlier when working on a CLI that I wanted to have some power user flags. For example, something like: ./cli create --name MyInput could help with cases where you would normally be prompted to enter a name.

My immediate thought was maybe adding a check before the prompt that checks if there's already an answer for the question, and if that answer passes validations, to skip the prompt portion. But then I can see how that opens up a whole other class of questions -- ie. How would a validation failure look? What if you just want pre-filled answers to be suggested defaults? What if you want them to skip validations?

Ultimately, it felt like I was trying to shoehorn my own business logic into the package, so I ended up managing those inputs on my end.

Simple Example:

var name string

func main() {
    ...
    if len(name) > 0 {
        fmt.Println(fmt.Sprintf("Name: %s", name))
        answers.Name = name
    ...
    } else {
        // questionsWithoutName is the array of survey.Question structs, with the Name question filtered out
    err := survey.Ask(questionsWithoutName, &answers)
    ...
    }
}

If you're running validations or transformations, things are likely a bit more complicated, but I was just working on something tiny, so this worked well enough.

[montanaflynn]

I also want to use a default and suggestions based on previous answers.

This would be very welcome, the syntax suggested seems reasonable.

[mislav]

Thanks everyone for the suggestions!

If your application needs subsequent questions to react to the answers of previous questions, you should go with multiple Asks:

if err := survey.Ask(questions1, &answers); err != nil {
  panic(err)
}
if err := survey.Ask(questions2, &answers); err != nil {
  panic(err)
}

That way you have absolute freedom to implement whichever logic you'd like.

Note that the Default property of Survey inputs is a Go value, not a reference. The provided value will be static and cannot change dynamically between survey prompts.