Use of async makes things difficult. Use promises instead.

[bendavis78]

I'm trying to use this in conjunction with printedjs, but it doesn't work because this library manipulates dom in a setTimeout(). Is there a good reason this needs to be wrapped in a setTimeout? If so, why not use promises? That would give us more control over the situation.

[T3sT3ro]

I modified the code and replaced current implementation with the following in my script:

function lineNumbersBlock (element, options) {
    if (typeof element !== 'object') return;

    return new Promise((resolve, reject) => {
        element.innerHTML = lineNumbersInternal(element, options);
        resolve();
    })
}

and it forks for me ¯\_(ツ)_/¯