R - kable() used in .Rmd does not show output in notebook

Question

I just started using kableExtra library to make my tables look better in the PDF output.
But when I use kable() function in R Notebook file, it does not show the output. Instead I see a large white space where the output should be.
Here is a screenshot:

When I Knit the file to PDF I can see the output.
Here is a screenshot:

Is there a way I can make the output appear both in the Notebook and PDF? Here is my code:

---
title: "R Notebook"
output:
  pdf_document: default
  html_notebook: default
---

```{r  message=FALSE, warning=FALSE}
library(knitr)
library(kableExtra)
library(dplyr)
#plot(cars)
```

```{r}
 cars %>% 
  slice(1:10) %>% 
  select(speed, dist) %>% 
  kable(format = "latex", booktabs = T) %>% 
  column_spec(column = 1:2, width = "0.5in")

```

Answer 1

You have to set a different kable format parameter for each output and specify results = 'asis' in chunk options.

For HTML / Notebook:

```{r, results='asis'}
cars %>% 
  slice(1:10) %>% 
  select(speed, dist) %>% 
  kable(format = "html", booktabs = T) %>% 
  column_spec(column = 1:2, width = "0.5in")
```

For PDF:

```{r, results='asis'}
cars %>% 
  slice(1:10) %>% 
  select(speed, dist) %>% 
  kable(format = "latex", booktabs = T) %>% 
  column_spec(column = 1:2, width = "0.5in")
```

Answer 2

I was having a similar problem, but it turns out that my editor theme's white default text was making the font in the .Rmd output invisible (but I could still highlight it).

My kable output was not working inside the .Rmd file--but was working fine when running the code in the console, and also when I knit the file. I was using the Idle Fingers editor theme (sort of a 'dark mode') and changing this to another theme fixed the issue.