aproba-overload

Hey,

I found your package tracing makara and adaro a couple months back and I found it really useful in a project I am now working on, so THANK YOU 👍 !

That said, I found my project to benefit from having a T/F returned for use in cases of function overloading via optional params.

TL;DR: I wrote a wrapper function which adds OR(|) and returns T/F if meets or doesn’t meet schema. Do you want it? I’ll make a PR.

My use case if a router function takes in multiple configurations.

• function (options, [callback]) {}
• function (template, dataObj, [options], [callback]) {}

After taking the information in, I parse into a single options object and call an internal function to do the actual work.

var q = require('q');
var extend = require('deep-extend');
var probe = require('./aproba-overload');

module.exports = {
  _compileOptions: {
    engine: null,
    template: null,
    data: null
  },
  _compile: function (options, callback) {
    var d = q.defer();

    // Do compile and resolve/reject promise

    return d.promise.nodeify(callback);
  },

  /**
   * Compile template
   * 
   * @param {String|Object} template   Either template name or options object
   * @param {Object}        [data]     data for template rendering
   * @param {Object}        [options]  optional object for options
   * @param {Function}      [callback] optional callback, returns promise of null
   * 
   * @return {q.Promise|null} promise if no callback, null if returned.
   */
  compile: function (template, data, options, callback) {
    var args = arguments;
    var opts = extend({}, module.exports._compileOptions);


    if (probe('O|OF', args)) { // Options with optional callback
      extend(opts, args[0]);
      callback = args[1];
    } else if (probe('SO|SOF', args)) { // template name and data, optional callback
      opts.template = args[0];
      opts.data = args[1];
      callback = args[2];
    } else if (probe('SOO|SOOF', args)) { // template name and data, additional template options, optional callback
      extend(opts, args[2]);
      opts.template = args[0];
      opts.data = args[1];
      callback = args[3];
    } else {
      throw new Error('Invalid Arguments'); // need more descriptive error message.
    }

    return module.exports._compile(opts, callback);
  }
};

Here is my wrapper:

/**
 * Filename: aproba-overload.js
 * Created by rhett on 2/22/16.
 */
'use strict';
var aproba = require('aproba');

var validate = module.exports = function (schema, args, throwErr) {

  // Enable OR syntax
  if (/.+\|.+/.test(schema)) {  // example schema = 'O|OF|O*F'
    var t = schema.split(/\|(.+)/); // t = ['O', 'OF|O*F', '']

    // return recursive for schema = 'O' OR recursive for schema = 'OF|O*F' <= which has another recurse
    return validate(t[0], args, throwErr) || validate(t[1], args, throwErr);
    // Todo: problem with throwErr here; If true passed it may not reach second call. Rethink this combo
  }

  try {
    aproba(schema, args);
  } catch (err) {
    if (!throwErr &&      // pass-through requested
      [
        'EMISSINGARG',
        'EUNKNOWNTYPE',
        'EINVALIDTYPE',
        'ETOOMANYARGS'
      ].indexOf(err.code) // Catch only known errors
    ) {
      return false;       // Doesn't meet schema
    } else {
      throw err;          // pass-through or other, unexpected error
    }
  }

  return true; // no problems, success
};

At the moment it is just a file in my libs, but I plan to later make into a tested module. Alternatively, I can make a pull request to add this into aproba if you are interested in having it.

If you think this code will be beneficial to you code base, tell me how you think it would be best to add. Otherwise, I’ll just make a new package.

Have a great day,

[dhollenbeck]

Perhaps use lowercase letters to indicate optional fnc params.

• function (options, [callback]) {} ==> aproba('Of')
• function (template, dataObj, [options], [callback]) {} ==> aproba('SOof')

I am only considering using this module so please do not consider my comment as an endorsement of this feature request.

[iarna]

What I’ve described is merged and published. As this implements the original request, I’m going to close this. If after trying this out any of you all are still interested in seeing sugar for optionals, please feel free to open a new issue.