Minimum number of lines (dynamic min height)

I’m aware that I can set the min height of of a dynamically resizing code mirror by using min-height in the Codemirror-Scroll, but if I want to define this in code (for different code mirror on the page), is my best option really to in JS, manually edit the codemirror-scroll class, to have a min-height equal to number_of_lines * line-height + padding and then convert that to em to account of user style sheet situations? As opposed to something like options.minLines = 4;

You can directly set editor.getScrollerElement().style.minHeight, if you call editor.refresh() afterwards.

There is no option for a minimum number of lines, however you can do something like this:

editor.setCursor(editor.lineCount(), 0); // Set the cursor at the end of existing content

var lineCount = editor.lineCount(); // current number of lines
var n = 10 - lineCount; // the minimum you want minus the current amount
var line = editor.getCursor().line;
var ch = editor.getCursor().ch;

// for every n, append a line		
for(i = 0; i < n; i++) {
	editor.replaceRange("\n" + ' ', { line });

This will not mess up your editor if your content extends the minimum lines.

Then set your codemirror height to fit-content or auto and the height will show all of the lines.

Here is an example.

For V6, you can do this:

function updateToMinNumberOfLines(editor, minNumOfLines) {

    const currentNumOfLines = editor.state.doc.lines;
    const currentStr = editor.state.doc.toString();

    if (currentNumOfLines >= minNumOfLines) {

    const lines = minNumOfLines - currentNumOfLines;

    const appendLines = "\n".repeat(lines);

        changes: {from: currentStr.length, insert: appendLines}