Question

Should the return value of SomeEditorFactory.getEditor(column) be a function or an object?

From the code

function getEditor(row, cell) {
    var column = columns[cell];
    var rowMetadata = data.getItemMetadata && data.getItemMetadata(row);
    var columnMetadata = rowMetadata && rowMetadata.columns;

    if (columnMetadata && columnMetadata[column.id] && columnMetadata[column.id].editor !== undefined) {
        return columnMetadata[column.id].editor;
    }
    if (columnMetadata && columnMetadata[cell] && columnMetadata[cell].editor !== undefined) {
        return columnMetadata[cell].editor;
    }

    return column.editor || (options.editorFactory && options.editorFactory.getEditor(column));
}

Not immediately obvious.

Answer 1

When SlickGrid calls YourEditorFactory.getEditor(column), it expects a function.