SOURCE

var split = (function () {
    let inline = {
        identifier: /^[a-zA-Z_$]+[a-zA-Z0-9_$]+/,
        str: /^['"]+.*['"]+/,
        char: /^[^\`\~\!@#\$\%\^\&\*\(\)\_\-\+\=\[\]\{\}\:\;\"\'\<\,\>\.\?\/\\\|\s]+/,
        space: /^\s+/,
        punct: /^[\`\~\!@#\%\^\&\*\(\)\-\+\=\[\]\{\}\:\;\<\,\>\.\?\/\\\|]/,
    }
    function split(str) {
        if (!str || typeof str != 'string') {
            return false;
        }
        let substr = str
        let cap = null
        let arr = []
        let len = 0;
        let matches = '';
        while (substr) {
            if ((cap = inline.identifier.exec(substr))) {
                matches = cap[0]
                len = matches.length
                arr.push(matches)
                substr = substr.slice(len)
            }
            if ((cap = inline.str.exec(substr))) {
                matches = cap[0]
                len = matches.length
                arr.push(matches)
                substr = substr.slice(len)
            }
            if ((cap = inline.char.exec(substr))) {
                matches = cap[0]
                len = matches.length
                arr.push(matches)
                substr = substr.slice(len)
            }
            if ((cap = inline.space.exec(substr))) {
                matches = cap[0]
                len = matches.length
                arr.push(matches)
                substr = substr.slice(len)
            }
            if ((cap = inline.punct.exec(substr))) {
                matches = cap[0]
                len = matches.length
                arr.push(matches)
                substr = substr.slice(len)
            }
        }
        return arr;
    }
    return split
})();
var parseElement = (function(){
    function parse(str) {
        let arr = split(str);
        let elems = [];
        for(let i = 0; i < arr.length; i++) {
            let str = `<span>${arr[i].replace(/\s/g,'&nbsp;')}</span>`;
            elems.push(str)
        }
        let style = `font-size: 14px;
        font-family: Consolas, monospace;
        letter-spacing: 0;
        line-height: 20px;
        `;
        let line = `<div class="line" style="${style}"><span>${elems.join("")}</span></div>`;
        return line;
    }
    return parse; 
})();
document.write(parseElement('let year = 2022;'))

* {
    margin: 0;
    padding: 0;
}