I've got a script displaying multiple words stored in a text array in some sort of typewriter style. However, the script stops after a few entries and does not run through all the words in the array as supposed to. Maybe I can't see the obvious issue, but please, can I get a hint?

Here's a pen of it: https://codepen.io/jackennils/pen/KKeVEbJ

document.addEventListener('DOMContentLoaded', function(event) {
    // array with texts to type in typewriter
    var dataText = ["Holz", "Schiefer", "Jeans", "Edelstahl", "Spiegel", "Acryl", "Leder", "Kork", "Fliesen", "Stein"];

    // type one text in the typwriter
    // keeps calling itself until the text is finished
    function typeWriter(text, i, fnCallback) {
        // check if text isn't finished yet
        if (i < (text.length)) {
            // add next character to span
            document.querySelector("span.mats").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, 1000);
        }
    }
    // start a typewriter animation for a text in the dataText array
    function StartTextAnimation(i) {
        if (typeof dataText[i] == 'undefined') {
            setTimeout(function() {
                StartTextAnimation(0);
            }, 0);
        }
        // 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);
});

body {
    background-color: #362871;
    height: 100%;
    font-family: 'Raleway', sans-serif;
}

p {
    font-size: 5em;
    color: white;
    text-transform: uppercase;
}

span.mats-inner {
    border-right: 20px solid;
    margin-left: 10px;
    animation: caret 1s steps(1) infinite;
}

@keyframes caret {
    50% {
        border-color: transparent;
    }
}

<p>Wir veredeln <span >mit Licht</span></p>

CodePudding user response：

It was really small logical mistake at the condition of the if statement.

if (i < dataText[i].length)

Here you are comparing i to the string length of the word but it has nothing to with string length. Instead, compare it with array length because it is fixed.

document.addEventListener('DOMContentLoaded', function(event) {
    // array with texts to type in typewriter
    var dataText = ["Holz", "Schiefer", "Jeans", "Edelstahl", "Acryl", "Leder", "Kork", "Fliesen", "Stein"];

    // type one text in the typwriter
    // keeps calling itself until the text is finished
    function typeWriter(text, i, fnCallback) {
        // check if text isn't finished yet
        if (i < (text.length)) {
            // add next character to span
            document.querySelector("span.mats").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, 1000);
        }
    }
    // start a typewriter animation for a text in the dataText array
    function StartTextAnimation(i) {
        console.log(i)
        if (typeof dataText[i] == 'undefined') {
            setTimeout(function() {
                StartTextAnimation(0);
            }, 0);
        }
        // check if dataText[i] exists
        if (i < dataText.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);
});

body {
    background-color: #362871;
    height: 100%;
    font-family: 'Raleway', sans-serif;
}

p {
    font-size: 5em;
    color: white;
    text-transform: uppercase;
}

span.mats-inner {
    border-right: 20px solid;
    margin-left: 10px;
    animation: caret 1s steps(1) infinite;
}

@keyframes caret {
    50% {
        border-color: transparent;
    }
}

<p>Wir veredeln <span >mit Licht</span></p>

CodePudding user response：

Your if statement logic is flawed. The line if (i < dataText[i].length) is checking if i (the index of the array) is less than the length of the string. After i gets high enough, it is higher than the lengths of most of the strings in the array. Your comment says that you are checking if dataText[i] exists. For that, you can use if (dataText[i]) {/* do whatever */}. This line checks if there is an entry located at the ith index of dataText. Hope this helped.