Now that you have seen how to create a simple “Hello World” recognizer.json file and use it with the provided matcher utility, let’s see how it can be used in the code. As in the previous tutorials, ensure that you have node and npm installed, create a new directory and initialize npm project there (accepting default values):

prompt> node -v
v6.9.4
prompt> npm -v
3.10.10
prompt> npm init

Note: if you don’t want to type in all the source code, you don’t have to. This tutorial is available as an npm module. Simply load the module, then copy all the files to your current directory:

prompt> npm install --save tui-usinghelloworld
prompt> cp node_modules/tui-usinghelloworld/* .

As the documentation for vui-ad-hoc-alexa-recognizer states you only need to 2 lines of code to use it. So, let’s see how it’s done. First, load the module:

// Load the vui-ad-hoc-alexa-recognizer so that we can use it
let vui = require('vui-ad-hoc-alexa-recognizer');

Second, load the recognizer.json file:

// Now load and parse the recognizer.json file
let recognizer = require('./recognizer.json');

Third, use it:

// Now make the actual call to match the text to intent 
let result = vui.Recognizer.matchText(stringToMatch, undefined, undefined, recognizer);

“Wait” you say - I am not stupid, that’s 3 lines of code! Well, you are right - the second part (loading the recognizer.json file) is optional. If this file is placed in the vui-ad-hoc-alexa-recognizer module’s directory and it’s named recognizer.json then vui-ad-hoc-alexa-recognizer will load it by default and you won’t need to provide it as an argument to matchText() call. I simply showed you how to load it explicitly, using its path.

So, now let’s add a few niceties, such as parsing out the arguments:

// Call this function to display instructions on the console on how to call index.js
// This isn't necessary, but a nice touch to have in case you come back to it and forget
// how to use it.
let usage = function(){
  console.log('Usage: node ' + process.argv[1] + ' "string to match"');
}

// Simple error checking - make sure we got all the arguments on the command line.
if (process.argv.length < 3) {
  usage();
  process.exit(1);
}
// Get the actual string that we should be matching
let stringToMatch = process.argv[2];

And finally, let’s log the result:

// Finally, print the result out to console and exit
console.log(JSON.stringify(result, null, 2));

Putting it all together you should have this index.js file:

'use strict'
// Load the vui-ad-hoc-alexa-recognizer so that we can use it
let vui = require('vui-ad-hoc-alexa-recognizer');

// Call this function to display instructions on the console on how to call index.js
// This isn't necessary, but a nice touch to have in case you come back to it and forget
// how to use it.
let usage = function(){
  console.log('Usage: node ' + process.argv[1] + ' "string to match"');
}

// Simple error checking - make sure we got all the arguments on the command line.
if (process.argv.length < 3) {
  usage();
  process.exit(1);
}
// Get the actual string that we should be matching
let stringToMatch = process.argv[2];

// Now load and parse the recognizer.json file
let recognizer = require('./recognizer.json');


// Now make the actual call to match the text to intent 
let result = vui.Recognizer.matchText(stringToMatch, undefined, undefined, recognizer);

// Finally, print the result out to console and exit
console.log(JSON.stringify(result, null, 2));

Now, let’s test it:

prompt> node index.js "Hi, how are you?"
{
  "name": "GreetingIntent",
  "slots": {}
}
prompt> node index.js "Hi, blah blah blah"
undefined

And there you have it - a simple script that uses a recognizer file.