client.js

'use strict';
// notes:
//
// * This file is bundled by exprss-browserify into bundle.js
//
// * The require('ibm-watson/language_translator/v3') could also be written as require('ibm-watson').LanguageTranslatorV3,
//   but that version results in a much larger bundle size.
//
// * Tokens expire after 1 hour. This demo simply fetches a new one for each translation rather than keeping a fresh one.
//
// * fetch() is a modern version of XMLHttpRequest. A pollyfill is available for older browsers: https://github.com/github/fetch

var ToneAnalyzerV3 = require('ibm-watson/tone-analyzer/v3');

var btn = document.getElementById('analyze-btn');
var input = document.getElementById('input');
var output = document.getElementById('output');

/**
 * @return {Promise<String>} returns a promise that resolves to a string token
 */
function getToken() {
  return fetch('/api/token/tone_analyzer').then(function (response) {
    return response.text();
  });
}

function analyze(token) {
  var toneAnalyzer = new ToneAnalyzerV3({
    token: token,
    version: '2016-05-19',
  });
  toneAnalyzer.tone(
    {
      text: input.value,
    },
    function (err, result) {
      if (err) {
        output.innerHTML = err;
        return console.log(err);
      }
      output.innerHTML = JSON.stringify(result, null, 2);
    }
  );
}

btn.onclick = function () {
  getToken().then(analyze);
};