How to use the natural.DiceCoefficient function in natural

var params = {
      text: 'How\'s it going?'
      , from: 'en'
      , to: 'ru'
    };

    // Don't worry about access token, it will be auto-generated if needed.
    client.translate(params, function(err, data) {
          console.log(data);
   	  console.log(err);
    });
*/


var natural = require('natural');
console.log(natural.DiceCoefficient("i want","want"))
// console.log(natural.JaroWinklerDistance('not', 'same'));
// console.log(natural.DiceCoefficient('thing', 'thing'));

nlp.DiceCoefficient = function (s1, s2) {
    return natural.DiceCoefficient(s1, s2);
};

_.forEach(this.features, (prop, name) => {
                      let delta = 0;
                      if (node.features[name] && _node.features[name] && (typeof node.features[name] === 'number') && (typeof _node.features[name] === 'number') && (this.features[name].range !== 0)) {
                        let difference = 0;
                        if (_node.features[name] > node.features[name]) difference = _node.features[name] - node.features[name]
                        else if (node.features[name] > _node.features[name]) difference = node.features[name] - _node.features[name]
                        delta = difference / (prop.max - prop.min);
                        let feature = Math.sqrt(delta * delta);
                        features.push(feature);
                      }
                      else if (node.features[name] && _node.features[name] && (typeof node.features[name] === 'string') && (typeof _node.features[name] === 'string') && (this.features[name].range !== 0)) {
                        if (this.stringAlgorithm === 'Jaro-Winkler') delta = natural.JaroWinklerDistance(node.features[name], _node.features[name]);
                        if (this.stringAlgorithm === 'Levenshtein') delta = natural.LevenshteinDistance(node.features[name], _node.features[name]);
                        if (this.stringAlgorithm === 'Dice') delta = natural.DiceCoefficient(node.features[name], _node.features[name]);
                        let feature = Math.sqrt(delta * delta);
                        features.push(feature);
                      }
                    });
                    arc.distance = features.length > 1 ? features.reduce((x, y) => x + y) : features[0];

var distance = function (X,Y)
{
    
    if ((X.length == 0) || (Y.length == 0))
        return 0
    return natural.DiceCoefficient(X.join(" "),Y.join(" "))    
}

_.forEach(this.features, (prop, name) => {
                  let delta = 0;
                  if (node.features[name] && _node.features[name] && (typeof node.features[name] === 'number') && (typeof _node.features[name] === 'number') && (this.features[name].range !== 0)) {
                    let difference = 0;
                    if (_node.features[name] > node.features[name]) difference = _node.features[name] - node.features[name];
                    if (node.features[name] > _node.features[name]) difference = node.features[name] - _node.features[name];
                    delta = difference / (prop.max - prop.min);
                    let feature = Math.sqrt(delta * delta);
                    features.push(feature);
                  }
                  else if (node.features[name] && _node.features[name] && (typeof node.features[name] === 'string') && (typeof _node.features[name] === 'string') && (this.features[name].range !== 0)) {
                    if (this.stringAlgorithm === 'Jaro-Winkler') delta = natural.JaroWinklerDistance(node.features[name], _node.features[name]);
                    if (this.stringAlgorithm === 'Levenshtein') delta = natural.LevenshteinDistance(node.features[name], _node.features[name]);
                    if (this.stringAlgorithm === 'Dice') delta = natural.DiceCoefficient(node.features[name], _node.features[name]);
                    let feature = Math.sqrt(delta * delta);
                    features.push(feature);
                  }
                });
                arc.distance = features.length > 1 ? features.reduce((x, y) => x + y) : 0;