x-posted from stack overflow - Teh Forum

<body> <div id="header"> <span class="left"> <span class="back"><a href="lthread_list.php?webtag=DEFAULT"><span class="image mobile_back" title="Back"></span></a></span> <span class="image mobile_logo" title="Beehive Forum Logo"></span> </span> <ul> <li> <a class="reply_all" href="lpost.php?webtag=DEFAULT&reply_to=42257.0&return_msg=42257.1"> <span class="image mobile_reply_all"></span><span class="text">Reply to All</span> </a> </li> <li> <a class="navigation" href="#"> <span class="image mobile_navigation"></span><span class="text">Show messages</span> </a> </li> <li> <a class="main" href="#"><span class="image mobile_menu" title="Menu"></span> </a> </li> </ul> </div> <div class="menu main"> <ul> <li><a href="lthread_list.php?webtag=DEFAULT">Messages</a></li> <li><a href="lpm.php?webtag=DEFAULT">Inbox</a></li> <li><a href="lsearch.php?webtag=DEFAULT">Search</a></li> <li><a href="llogon.php?webtag=DEFAULT">Login</a></li> </ul> </div> <div class="menu navigation"><a href="lmessages.php?webtag=DEFAULT&msg=42257.1">1–10</a><a href="lmessages.php?webtag=DEFAULT&msg=42257.11">11–12</a></div> <div id="page_content"> <h3 class="thread_title"><a href="index.php?webtag=DEFAULT&amp;msg=42257.1">x-posted from stack overflow</a> </h3> <div id="messages" data-navigation="42257_1_12_10"> <a name="a42257_1"></a><div class="message" id="message_42257_1"> <div class="message_header"> <div class="message_from"> From: CHYRON (DSMITHHFX)<span class="message_time">30 Oct 2018 14:23</span> <div class="clearer"></div> </div><div class="message_to">To: ALL<span class="message_count">1 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.1">42257.1</a></div> <div class="message_body"> (thought I'd run it past teh while I'm at it spinning my tires for the past 3-hours <span class="emoticon e_sad" title=":-("><span class="e__">:-(</span></span> ) <div class="votecell post-layout--left"> <div class="vote"> <div class="favoritecount"> </div> </div> </div> <div class="postcell post-layout--right"> <div class="post-text"> <p>I'm trying to add items from a modified list of thumbs to a service worker storage cache by JSON import.</p> <p>Everything's working as far as generating a correctly-formatted and complete array of thumbs to cache -- <span style="color:#c0392b;">console.log(cacheArray)</span> inside the <span style="color:#c0392b;">for</span> statement -- but I can't seem to get a final array out of the function -- <span style="color:#c0392b;">console.log('updateCache: ' + cacheArray)</span> returns a blank:</p> <pre class="default prettyprint prettyprinted"> <span class="pln"> fetch</span><span class="pun">(</span><span class="str">'alldates.txt'</span><span class="pun">).</span><span class="kwd">then</span><span class="pun">(</span><span class="kwd">function</span><span class="pun">(</span><span class="pln">response</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="kwd">return</span><span class="pln"> response</span><span class="pun">.</span><span class="pln">text</span><span class="pun">();</span><span class="pln"> </span><span class="pun">}).</span><span class="kwd">then</span><span class="pun">(</span><span class="kwd">function</span><span class="pun">(</span><span class="kwd">string</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="kwd">var</span><span class="pln"> alldatesobj </span><span class="pun">=</span><span class="pln"> JSON</span><span class="pun">.</span><span class="pln">parse</span><span class="pun">(</span><span class="kwd">string</span><span class="pun">);</span><span class="pln"> </span><span class="kwd">var</span><span class="pln"> cacheThumb</span><span class="pun">;</span><span class="pln"> </span><span class="kwd">var</span><span class="pln"> thumbslist </span><span class="pun">=</span><span class="pln"> </span><span class="typ">Object</span><span class="pun">.</span><span class="pln">values</span><span class="pun">(</span><span class="pln">alldatesobj</span><span class="pun">);</span><span class="pln"> </span><span class="kwd">var</span><span class="pln"> cacheArray </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Array</span><span class="pun">();</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> updateCache</span><span class="pun">(</span><span class="pln">cacheArray</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="kwd">for</span><span class="pun">(</span><span class="pln">i </span><span class="pun">=</span><span class="pln"> </span><span class="lit">1</span><span class="pun">;</span><span class="pln"> i </span><span class="pun"><=</span><span class="pln"> thumbslist</span><span class="pun">.</span><span class="pln">length</span><span class="pun">;</span><span class="pln"> i</span><span class="pun">++)</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> cacheThumb </span><span class="pun">=</span><span class="pln"> thumbslist</span><span class="pun">[</span><span class="pln">i</span><span class="pun">].</span><span class="pln">replace</span><span class="pun">(</span><span class="str">'100315'</span><span class="pun">,</span><span class="pln"> </span><span class="str">'100315/thumbs'</span><span class="pun">);</span><span class="pln"> cacheArray</span><span class="pun">.</span><span class="pln">push</span><span class="pun">(</span><span class="pln">cacheThumb</span><span class="pun">);</span><span class="pln"> </span><span class="com">//console.log(cacheArray.slice(-1)[0]);</span><span class="pln"> </span><span class="com">//console.log(cacheArray);</span><span class="pln"> </span><span class="com">//^^^ array is correctly formed!!!</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="kwd">return</span><span class="pln"> cacheArray</span><span class="pun">;</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> updateCache</span><span class="pun">(</span><span class="pln">console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class="str">'updateCache: '</span><span class="pln"> </span><span class="pun">+</span><span class="pln"> cacheArray</span><span class="pun">));</span><span class="pln"> </span><span class="pun">});</span></pre> </div> </div> <div class="edit_text">EDITED: 30 Oct 2018 14:35 by DSMITHHFX</div> </div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.1&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.1"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_2"></a><div class="message" id="message_42257_2"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">30 Oct 2018 19:25</span> <div class="clearer"></div> </div><div class="message_to">To: CHYRON (DSMITHHFX) <span><span class="image post_read" title="Read: 30 Oct 2018 19:35"></span></span> <span class="message_count">2 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.2">42257.2</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_1" target="_self">42257.1</a></div> <div class="message_body"> Should cacheArray be populated with an array after the updateCache function?<br /><br /> I've not done much JS but I think you want to pass the empty array to updateCache to populate it, then print it out? updateCacheArray expected the cacheArray array, but you're passing the console.log to it. So instead of updateCache(console....) you'd do<br /> updateCache(cacheArray);<br /> console.log(cacheArray);</div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.2&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.2"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_3"></a><div class="message" id="message_42257_3"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">30 Oct 2018 19:27</span> <div class="clearer"></div> </div><div class="message_to">To: Chris (CHRISSS) <span><span class="image post_read" title="Read: 30 Oct 2018 19:27"></span></span> <span class="message_count">3 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.3">42257.3</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_2" target="_self">42257.2</a></div> <div class="message_body"> Or, if this works: <pre> console.log('updateCache: ' + updateCache(cacheArray));</pre> </div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.3&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.3"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_4"></a><div class="message" id="message_42257_4"> <div class="message_header"> <div class="message_from"> From: CHYRON (DSMITHHFX)<span class="message_time">30 Oct 2018 19:51</span> <div class="clearer"></div> </div><div class="message_to">To: Chris (CHRISSS) <span><span class="image post_read" title="Read: 30 Oct 2018 19:54"></span></span> <span class="message_count">4 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.4">42257.4</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_3" target="_self">42257.3</a></div> <div class="message_body"> Nope, function either fails silently, or passes the original, empty array variable.<br /><br /> Weird thing is it logs the array build perfectly all the way to completion from inside the "for" statement, just can't get at the built array outside.<div class="edit_text">EDITED: 30 Oct 2018 19:55 by DSMITHHFX</div> </div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.4&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.4"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_5"></a><div class="message" id="message_42257_5"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">30 Oct 2018 19:55</span> <div class="clearer"></div> </div><div class="message_to">To: CHYRON (DSMITHHFX) <span><span class="image post_read" title="Read: 30 Oct 2018 19:55"></span></span> <span class="message_count">5 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.5">42257.5</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_1" target="_self">42257.1</a></div> <div class="message_body"> cacheArray = updateCacheArray(cacheArray); ?</div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.5&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.5"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_6"></a><div class="message" id="message_42257_6"> <div class="message_header"> <div class="message_from"> From: Peter (BOUGHTONP)<span class="message_time">30 Oct 2018 23:03</span> <div class="clearer"></div> </div><div class="message_to">To: CHYRON (DSMITHHFX) <span><span class="image post_read" title="Read: 31 Oct 2018 00:29"></span></span> <span class="message_count">6 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.6">42257.6</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_1" target="_self">42257.1</a></div> <div class="message_body"> <p>You should pick either passing in <em>all</em> the variables as arguments, or fully using closure - doing a mix of both is confusing, and is going to be the reason for your bug - you have two different cacheArray variables, and you're not assigning the inner one to the outer one. </p><p>What does alldates.txt contain? </p><p>If it's already an array then you can just do:</p><pre>var cacheArray = JSON.parse(string).map (function(item){ return item.replace(/100315/,'$&/thumbs'); });</pre> <p>If the Object.values is needed you can still use map:</p><pre>var cacheArray = Object.values(alldatesobj).map (function(item){ return item.replace(/100315/,'$&/thumbs'; });</pre> <p>The $& means whatever is matched (pretty much everyone else uses $0 or \0 but JS has to be awkward). </p><p>Also, on a general note, you can't trust console.log in modern browsers - they do <strong>not</strong> tell you a variable's value at the point when you're logging it but have started looking it up after - you need to use <tt>console.log(JSON.stringify(variabletolog))</tt> to freeze it and get a correct report.</p><div class="edit_text">EDITED: 30 Oct 2018 23:05 by BOUGHTONP</div> </div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.6&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.6"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_7"></a><div class="message" id="message_42257_7"> <div class="message_header"> <div class="message_from"> From: CHYRON (DSMITHHFX)<span class="message_time">31 Oct 2018 12:21</span> <div class="clearer"></div> </div><div class="message_to">To: Peter (BOUGHTONP) <span><span class="image post_read" title="Read: 31 Oct 2018 22:43"></span></span> <span class="message_count">7 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.7">42257.7</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_6" target="_self">42257.6</a></div> <div class="message_body"> <strong>Quote:</strong> <div class="quote"> <pre> var cacheArray = Object.values(alldatesobj).map (function(item){ return item.replace(/100315/,'$&/thumbs'; });</pre> </div> Yeah that works! <span class="emoticon e_bounce" title="(bounce)"><span class="e__">(bounce)</span></span><br /><br /> I had read about the map function, but according to some folks somewhere on the internet, it should not be needed and costs more cpu cycles (or something).<br /> <div class="quotetext"><strong>Quote:</strong> </div> <div class="quote">What does alldates.txt contain?</div> <br /> It's an array with key-value pairs, keys are 4-digit dates (mmdd), values are image names (*.jpg) used to display a specific new image each day here:<br /><a href="http://designartcraft.com/photo/afbp.htm">http://designartcraft.com/photo/afbp.htm</a> and randomly here:<br /><a href="http://designartcraft.com/photo/random.html">http://designartcraft.com/photo/random.html</a><br /><br /><br /> The purpose of all this is to cache thumbs (same names, in "/thumbs") for offline.<br /><br /> I'm slowly trying to get up to speed on modren javascript syntax without relying on jquery (which doesn't work in service workers). Long ways to go, obviously.<br /><br /> Thanks!<br /><br /> <div class="edit_text">EDITED: 31 Oct 2018 12:32 by DSMITHHFX</div> </div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.7&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.7"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_8"></a><div class="message" id="message_42257_8"> <div class="message_header"> <div class="message_from"> From: Peter (BOUGHTONP)<span class="message_time">31 Oct 2018 23:34</span> <div class="clearer"></div> </div><div class="message_to">To: CHYRON (DSMITHHFX) <span><span class="image post_read" title="Read: 1 Nov 2018 09:11"></span></span> <span class="message_count">8 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.8">42257.8</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_7" target="_self">42257.7</a></div> <div class="message_body"> <i>> it should not be needed and costs more cpu cycles (or something).</i> <p>The same can be said for anything that isn't assembly language. </p><p>There's no situation where map is <em>necessary</em> - it can always be replaced with a loop - but there's plenty of situations when it makes code easier to understand and work with, and that should generally be the primary concern for the first iteration of any code. (Which isn't to say always use map - it's possible to misuse just like any construct - but don't be afraid to use it when suitable.) </p><p>Performance matters when you can show the difference - if a web script takes half a second to run, then absolutely spend some time to identify and optimise the slowest aspect (and that's not always the most obvious one), but if its 38ms vs 35ms then it's less likely to matter. </p><p><br /></p><p>><i> I'm slowly trying to get up to speed on modren javascript syntax without relying on jquery</i> </p><p>I recently decided to write a jquery-free library for scattering images, and it's interesting to see what's now possible and how browser vendors have still managed to over-complicate simple tasks. </p><p>I found <a href="https://developer.mozilla.org/en-US/">MDN</a> to be the best resource, although sometimes you need to know what to look for first - definitely useful for getting the right polyfills if you want to support older browsers whilst still using modern methods.</p></div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.8&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.8"> <span class="rating">+1/1</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_9"></a><div class="message" id="message_42257_9"> <div class="message_header"> <div class="message_from"> From: CHYRON (DSMITHHFX)<span class="message_time"> 1 Nov 2018 09:18</span> <div class="clearer"></div> </div><div class="message_to">To: Peter (BOUGHTONP) <span><span class="image post_read" title="Read: 1 Nov 2018 21:30"></span></span> <span class="message_count">9 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.9">42257.9</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_8" target="_self">42257.8</a></div> <div class="message_body"> I'm using MDN quite a lot. Explanations are sparse, useful examples rare, and there's an assumption of underlying familiarity with syntax that can make it pretty difficult to follow. </div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.9&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.9"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42257_10"></a><div class="message" id="message_42257_10"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time"> 1 Nov 2018 20:15</span> <div class="clearer"></div> </div><div class="message_to">To: Peter (BOUGHTONP) <span><span class="image post_read" title="Read: 1 Nov 2018 21:30"></span></span> <span class="message_count">10 of 12</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42257.10">42257.10</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42257.1#a42257_8" target="_self">42257.8</a></div> <div class="message_body"> What is polyfill?</div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42257.10&return_msg=42257.1" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42257.10"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div></div> <div class="message_page_footer"> <ul> <li class="right_col"><form accept-charset="utf-8" method="get" action="lmessages.php" target="_self"><input type="hidden" name="webtag" id="webtag" class="bhinputtext" value="DEFAULT" dir="ltr" /><input type="hidden" name="msg" id="msg" class="bhinputtext" value="42257.11" dir="ltr" /><input type="submit" name="submit" id="keep_reading" value="Keep reading…" class="button" /></form></li> </ul> </div> </div> </body>