Tests 
Testing the rendering of observablehq notebooks in markdown.
Options 
Regular js code block 
md
```js
const mol = 40 + 2;
```Produces:
js
const mol1 = 40 + 2;Executed code block 
md
```js exec
mol = 40 + 2;
```Produces:
mol = 40 + 2;Executed code block with echo 
md
```js exec echo
molSrcEcho = 40 + 2;
```Produces:
molSrcEcho = 40 + 2;js
molSrcEcho = 40 + 2;Executed code block with hide 
md
```js exec hide
molSrcHide = 40 + 2;
```Produces:
WARNING
Both the code block and executed output is hidden but the result is still calculated.
Executed code block with echo and hide 
md
```js exec echo hide
molSrcEchoHide = 40 + 2;
```Produces:
js
molSrcEchoHide = 40 + 2;aaa
a mol b
R2D2
a ${ mol } bjs