I have tried it stand alone like this:
<SPAN class="" style="border: 0px; font-size: 13px;">myLayer</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">popupTemplate </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">{</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;"><---</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> have also tried defining </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">this</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> as popupShake title</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">:</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">function</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">feature</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">)</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">{</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">let</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> spl </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> document</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">createElement</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"span"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">);</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> spl</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">className </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"name_plc"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> spl</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">innerHTML </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"<span class='name_plc'></span>"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">return</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> spl</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">}</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">};</SPAN>
I have also tried it inline within the popuptemplate call (such as the content section, but title will not run even though documentation states it accepts strings and OR functions).
i.e.
<SPAN class="" style="border: 0px; font-weight: inherit; font-size: 13px;"> </SPAN><STRONG><SPAN class="" style="border: 0px; font-size: 13px;">let</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> popupShake </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">{</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> outFields</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">:</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">[</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"*"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">],</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"title"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">:</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">function</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">feature</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">){</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;"><-------------</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> breaks popup</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">,</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> but content below works </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">let</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> spl </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> document</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">createElement</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"span"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">);</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> spl</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">className </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"name_plc"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> dlv</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">innerHTML </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"<span class='name_plc'></span>"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">return</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> spl</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">},</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"content"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">:</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">function</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">feature</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">){</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">let</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> name_plc</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">let</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> dlv </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> document</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">createElement</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">(</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"div"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">);</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> dlv</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">className </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"popd"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> dlv</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">innerHTML </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">`<</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">b</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">><</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">span </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">class</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">'name_plc'</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">><</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">/span></</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">b</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">><</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">br</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">></SPAN><SPAN class="" style="border: 0px; font-size: 13px;">ID</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">:</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;"><</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">span </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">class</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">"ida"</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">></SPAN><SPAN class="" style="border: 0px; font-size: 13px;">$</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">{</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">feature</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">graphic</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">attributes</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">id</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">}<</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">/span><br> URL: <a href="${feature.graphic.attributes.url}" target="_blank">View</</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">a</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">></SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;"><</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">br</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">></SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">Updated</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">:</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> $</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">{</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">feature</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">graphic</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">attributes</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">updated</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">}</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;"><</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">br</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">></SPAN><SPAN class="" style="border: 0px; font-size: 13px;">Grid_value</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">:</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> $</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">{</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">feature</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">graphic</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">attributes</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">grid_value</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">}<</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">br</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">></SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">Event</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">Time</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">:</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> $</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">{</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">feature</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">graphic</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">attributes</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">.</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">eventTime</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">}`;</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> setTimeout</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">(()</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">=></SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">{</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> getName</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">();</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">},</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">20</SPAN><SPAN class="" style="border: 0px; font-size: 13px;">);</SPAN><SPAN class="" style="border: 0px; font-size: 13px;"> </SPAN><SPAN class="" style="border: 0px; font-size: 13px;">................</SPAN></STRONG>