In 2017 Kelly Gerrow shared a great blog on https://community.esri.com/community/gis/web-gis/arcgisonline/blog/2017/07/18/conditional-field-display-with-arcade-in-pop-ups , but there are still a lot of questions on how to hide rows of a table that do not have values. In this document I will try to explain how to do this with Arcade in a web map.
I have a feature layer, added 3 fields and randomly created some data including null values:

The idea is to create a table that will show the 3 rows when all 3 field have a value and hides each row that are empty:

So how can we hide rows and not leaving empty lines? This can be done by using a style that shows or not shows the row, which can be conditionally done using Arcade. See below the HTML used in the example above:
Information before table<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>table</SPAN><SPAN class="punctuation token">></SPAN></SPAN><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>tbody</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>tr</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="selector token">display:</SPAN><SPAN class="punctuation token">{</SPAN>expression/expr0<SPAN class="punctuation token">}</SPAN></SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>td</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN>125px<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">text-align</SPAN><SPAN class="punctuation token">:</SPAN>left<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">background-color</SPAN><SPAN class="punctuation token">:</SPAN>#ede8e8<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">padding</SPAN><SPAN class="punctuation token">:</SPAN>5px</SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>Description 1<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>td</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>td</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN>225px<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">text-align</SPAN><SPAN class="punctuation token">:</SPAN>left<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">background-color</SPAN><SPAN class="punctuation token">:</SPAN>#ede8e8<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">padding</SPAN><SPAN class="punctuation token">:</SPAN>5px</SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>{Field1}<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>td</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>tr</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>tr</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="selector token">display:</SPAN><SPAN class="punctuation token">{</SPAN>expression/expr1<SPAN class="punctuation token">}</SPAN></SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>td</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN>125px<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">text-align</SPAN><SPAN class="punctuation token">:</SPAN>left<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">background-color</SPAN><SPAN class="punctuation token">:</SPAN>#ede8e8<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">padding</SPAN><SPAN class="punctuation token">:</SPAN>5px</SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>Description 2<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>td</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>td</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN>225px<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">text-align</SPAN><SPAN class="punctuation token">:</SPAN>left<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">background-color</SPAN><SPAN class="punctuation token">:</SPAN>#ede8e8<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">padding</SPAN><SPAN class="punctuation token">:</SPAN>5px</SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>{Field2}<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>td</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>tr</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>tr</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="selector token">display:</SPAN><SPAN class="punctuation token">{</SPAN>expression/expr2<SPAN class="punctuation token">}</SPAN></SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>td</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN>125px<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">text-align</SPAN><SPAN class="punctuation token">:</SPAN>left<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">background-color</SPAN><SPAN class="punctuation token">:</SPAN>#ede8e8<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">padding</SPAN><SPAN class="punctuation token">:</SPAN>5px</SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>Description 3<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>td</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"><</SPAN>td</SPAN><SPAN class="style-attr language-css token"><SPAN class="attr-name token"> <SPAN class="attr-name token">style</SPAN></SPAN><SPAN class="punctuation token">="</SPAN><SPAN class="attr-value token"><SPAN class="property token">width</SPAN><SPAN class="punctuation token">:</SPAN>225px<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">text-align</SPAN><SPAN class="punctuation token">:</SPAN>left<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">background-color</SPAN><SPAN class="punctuation token">:</SPAN>#ede8e8<SPAN class="punctuation token">;</SPAN> <SPAN class="property token">padding</SPAN><SPAN class="punctuation token">:</SPAN>5px</SPAN><SPAN class="punctuation token">"</SPAN></SPAN><SPAN class="punctuation token">></SPAN></SPAN>{Field3}<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>td</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>tr</SPAN><SPAN class="punctuation token">></SPAN></SPAN>
<SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>tbody</SPAN><SPAN class="punctuation token">></SPAN></SPAN><SPAN class="token tag"><SPAN class="token tag"><SPAN class="punctuation token"></</SPAN>table</SPAN><SPAN class="punctuation token">></SPAN></SPAN>Information after table<SPAN class="line-numbers-rows"><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN><SPAN></SPAN></SPAN>In this case there are 3 Arcade expressions. Each expression will validate if an attribute has a value or is empty. In case it is empty it will return "none" (hide the row) en in case it has a value it will return "block" (show the row). See below the expression to validate field 1 (the same is done for fields 2 and 3):
<SPAN class="token function">IIf</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="token function">IsEmpty</SPAN><SPAN class="punctuation token">(</SPAN>$feature<SPAN class="punctuation token">.</SPAN>Field1<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"none"</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">"block"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN><SPAN class="line-numbers-rows"><SPAN></SPAN></SPAN>
If you have any questions, just post them below.