React JS Uncaught Reference Error: function not defined
<p>I am trying to call shuffleCards when the upon a click event in a ReactJs component. However, I am receiving the following error: </p>

<pre><code>Uncaught ReferenceError: shuffleCards is not defined
</code></pre>

<p>Here's my code:</p>

<pre><code>constructor(props) {
    super(props);

    this.state = {
        count: 0
    };
}

shuffleCards(array) {
    var i = array.length,
        j = 0,
        temp;

    while (i--) {
        j = Math.floor(Math.random() * (i+1));

        temp = array[i];
        array[i] = array[j];
        array[j] = temp;
    }
    return array;
}

handleClickEvent(event) {
    var cards = [
        {txt: "A",
        isDisplayed: false},
        {txt: "B",
        isDisplayed: false},
        {txt: "C",
        isDisplayed: false}
    ];
    if (this.state.count == 0) {
        cards = shuffleCards(cards);
    }

}
</code></pre>