font previewer thingy

<div>
    <script>
        window.fontTesterOptions = {
            characters: 'aimepytgdobh',
            initial: `
                imbody
                empathy
            `,
        };
    </script>
    <style>
        .font-tester-container {
            --colour-text: black;
            --colour-background: rgba(0, 0, 0, .02);
            --font-name: "wonky";
        }

        @font-face {
            font-family: "wonky";
            /* Add other properties here, as needed. For example: */
            /*
            font-weight: 100 900;
            font-style: normal italic;
            */
            src: url(data:application/font-woff;base64,/*truncated for ur convenience xdd*/);
        }

        #font-tester {
            line-height: 2em;
            text-align: center;
            font-family: var(--font-name);
            font-size: 5rem;
            border: 0;
            background: var(--colour-background);
            color: var(--colour-text);
            box-sizing: border-box;
            padding: 5rem;
            transition: none !important;
        }

        .font-tester-container {
            width: 100%;
            display: flex;
            justify-content: center;
            align-items: center;
        }
    </style>
    <div class="font-tester-container">
      <textarea id="font-tester"></textarea>
    </div>
    <script>
        (() => {
            const fontTesterElem = document.getElementById('font-tester');
            const charactersRegex = new RegExp(
                // escaped characters + space + newline
                `[${window.fontTesterOptions.characters.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')}\n ]`
            );

            fontTesterElem.textContent = window
                .fontTesterOptions
                .initial
                    .trim()
                    .replace(/ {4}|\t/g, '');

            fontTesterElem.addEventListener(
                'keypress',
                (event) => charactersRegex.test(event.key) || event.preventDefault(),
            );

            new IntersectionObserver(
                (entry) => {
                    if (!entry[0].isIntersecting) return;
                    fontTesterElem.focus();
                    // move cursor to end
                    fontTesterElem.selectionEnd = fontTesterElem.selectionStart = fontTesterElem.textContent.length;
                },
                { threshold: 0.5 },
            )
                .observe(fontTesterElem);
        })();
    </script>
</div>