Rubygem and Node Package both return nil/null about oakdex-pokedex HOT 4 CLOSED

var oakdex = require('oakdex-pokedex');
oakdex.findPokemon(number, function(p) {
            console.log(p.names.en);
});
// cannot read property 'names' of undefined

let prepareQuestions = function(pokemonList) {
    let questionList = [];
    for (let pokemon of pokemonList) {
        Oakdex.findPokemon(pokemon, function(p) {
            let types = p.types;      // This is the error line below (index.js:43:26)
            questionList.push({question: pokemon, answer: types})
        });
    }
    
    return questionList;
}

module initialization error: TypeError
    at /var/task/index.js:43:26
    at /var/task/node_modules/oakdex-pokedex/src/oakdex_pokedex.js:106:13
    at /var/task/node_modules/oakdex-pokedex/src/oakdex_pokedex.js:47:5
    at allByName (/var/task/node_modules/oakdex-pokedex/src/oakdex_pokedex.js:9:5)
    at pokemonById (/var/task/node_modules/oakdex-pokedex/src/oakdex_pokedex.js:43:3)
    at /var/task/node_modules/oakdex-pokedex/src/oakdex_pokedex.js:103:9
    at allByName (/var/task/node_modules/oakdex-pokedex/src/oakdex_pokedex.js:9:5)
    at Object.findPokemon (/var/task/node_modules/oakdex-pokedex/src/oakdex_pokedex.js:100:5)
    at prepareQuestions (/var/task/index.js:41:16)
    at Object.<anonymous> (/var/task/index.js:51:22)