JSPM

Intro

yesno is a super simple nodejs library for issuing and handling responses to boolean (or rather, binary) questions

Installation

npm install yesno

API

Promise based (returns a promise):

askAsync(
    <string> question, 
    <boolean|null> default_value,
    <array|null> yes_values,
    <array|null> no_values
)

Callback based:

ask(
    <string> question, 
    <boolean|null> default_value,
    <function> response_handler,
    <array|null> yes_values,
    <array|null> no_values
)

If yes_values or no_values aren't supplied, yesno falls back on accepting yes, y , no, and n.

All yesno responses are case insensitive.

Example

var yesno = require('yesno');

yesno.ask('Are you sure you want to continue?', true, function (ok) {
    if (ok) {
        console.log("Yay!");
    } else {
        console.log("Nope.");
    }
});

Examples

Custom Yes/No response values

var yesno = require('yesno');

yesno.ask('Dude, Is this groovy or what?',true, function (ok) {
    if (ok) {
        console.log("Tubular.");
    } else {
        console.log("Aw, why you gotta be like that?")
    }
}, ['groovy'], ['or what']);

Now the question only responds to groovy as yes and or what as no.

Promisified ask

If you're on a newer version of node (8+) you can use the promisified askAsync function:

var yesno = require('yesno');

async function main() {
    var ok = await yesno.askAsync('Are you sure you want to continue?', true);
    if (ok) {
        console.log('Yay!');
    } else {
        console.log('Nope.');
    }
}

main();

No default value

Sometimes you may want to ensure the user didn't accidentally accept a default. You can disable the default response by passing null as the default_value parameter

var yesno = require('yesno');

var handleResponse = function (ok) {
    ...
};

yesno.ask("Are you sure you want to 'rm-rf /' ?", null, handleResponse);

Globally changing Yes/No respones values

You can change the built in yes/no accepted responses by altering yesno's options attribute:

var yesno = require('yesno');

yesno.options.yes  = [ 'ja', 'si' ];
yesno.options.no   = [ 'nein', 'no' ];

Handling invalid responses

By default, if the user enters a value that isn't recognized as an acceptable response, it will print out a message like:

Invalid response.
Answer either yes : (yes, y)
Or no : (no, n)

and re-ask the question. If you want to change this behavior, you can set the invalid handler before asking your question:

var yesno = require('yesno');

yesno.onInvalidHandler(function (question, default_value, callback, yes_values, no_values) {
    process.stdout.write("\n Whoa. That was not a good answer. Well. No more tries for you.");
    process.exit(1);
});

// ask a question

Todo

• Allow supplying your own stdin/stdout streams so it doesn't always write to the process?
• Put in some error handling