#js #snippet #prompt2 Generic function that extends `window.prompt()`.

prompt2.js

/**
    `result = prompt2([prompt , options|default]);`

    Generic function that extends `window.prompt()`.
    If `options.validate()` is provided, this function will loop until the function return true on user's input.
    
    Empty string (`''`) will be used instead of passing `undefined` for `prompt` and `default`.

    If an non-Object is passed for options, it will be used as default value 
    (compatible with `window.prompt()`, no validation is performed). Use 
    `options.defaultValue` to pass an Object as default value.

    *Arguments*:
    # `prompt` (String): The text to display to the user
    # `options` (Object): Option object with the following properties:
        `defaultValue`: User specified default value
        `validate` (Function): The function called to validate result
    # `default` (non Object): User specified default value
*/
function prompt2(prompt, options) {
    var promptString = (prompt !== 'undefined')? prompt:'';
    var defaultValue = '';
    var opts = {};
    if (typeof options !== 'undefined') {
        if (typeof options === 'object') {
            opts = options;
        }
        else {
            defaultValue = options;
        }
    }
    // default validate(), no-op
    var validate = function (result) {
        return true;
    };

    if (typeof opts.defaultValue !== 'undefined') {
        defaultValue = opts.defaultValue;
    }
    if (typeof opts.validate === 'function') {
        validate = opts.validate;
    }

    var result = null;
    do {
        // do-while is better then while-break here
        result = window.prompt(promptString, defaultValue);
    } while (!validate(result));

    return result;
}