无法读取未定义的属性“长度”-JavaScript中的错误

我正在使用可再现打字机效果的代码来学习html / css / js中的动画。一切正常，但是我在控制台上不断收到此错误：

**script.js:33 Uncaught TypeError: Cannot read property 'length' of undefined
at StartTextAnimation (script.js:33)
at script.js:37**

我尝试了一些在Google上找到的解决方案，但没有任何效果。在我的console.log（dataText）中，数组中的每个字符串都正确执行。该错误在执行循环的那一刻出现。

这是我现在正在处理的代码：

document.addEventListener('DOMContentLoaded', function(event) {
    // array with texts to type in typewriter
    var dataText = ["Cyber", "Sapa", "Synth", "CYBER // SAPA // SYNTH // TÔRTA // POMBADEV.2020"];

    // type one text in the typwriter
    // keeps calling itself until the text is finished
    function typeWriter(text, i, fnCallback) {

        // chekc if text isn't finished yet
        if (i < (text.length)) {
            // add next character to h2
            document.querySelector("h2").innerHTML = text.substring(0, i + 1) + '<span aria-hidden="true"></span>';

            // wait for a while and call this function again for next character
            setTimeout(function() {
                typeWriter(text, i + 1, fnCallback)
            }, 100);
        }
        // text finished, call callback if there is a callback function
        else if (typeof fnCallback == 'function') {
            // call callback after timeout
            setTimeout(fnCallback, 700);
        }
    }
    // start a typewriter animation for a text in the dataText array
    function StartTextAnimation(i) {
        if (typeof dataText[i] == 'undefined') {
            setTimeout(function() {
                StartTextAnimation(0);
            }, 5000);
        }
        // check if dataText[i] exists
        if (i < dataText[i].length) {
            // text exists! start typewriter animation
            typeWriter(dataText[i], 0, function() {
                // after callback (and whole text has been animated), start next text
                StartTextAnimation(i + 1);
            });
        }
    }
    // start the text animation
    StartTextAnimation(0);
});

如果有人可以帮助我，我将不胜感激！

PS。Codepen链接：https：//codepen.io/iMorettini/pen/rNMOvZK