angular - Elvis Operator with *ngFor -

-

is legal use elvis operator *ngfor (place question mark after users, since array might null @ moment)?

<tr *ngfor="#user of users?">   <td> {{user.username}}</td> </tr

if array users null, elvis operator in {{user.username}} redundant because <td>...</td> never gets created , {{user.username}} isn't evaluated @ all.


Comments

Post a Comment

Popular posts from this blog

javascript - Feed FileReader from server side files -

-
i´m starting customize/improve old audio editor project. can import audio tracks canvas via drag&drop computer. thing use audio tracks stored in server clicking on list of available tracks... instead of use <input type="file"> tags. how can read server side files filereader?ajax perhaps? in advance. this code file reader: player.prototype.loadfile = function(file, el) { //console.log(file); var reader = new filereader, filetypes = ['audio/mpeg', 'audio/mp3', 'audio/wave', 'audio/wav'], = this; if (filetypes.indexof(file.type) < 0) { throw('unsupported file format!'); } reader.onloadend = function(e) { if (e.target.readystate == filereader.done) { // done == 2 $('.progress').children().width('100%'); var onsuccess = function(audiobuffer) { $(el).trigger('audiee:fileloaded', [audiobuffer, file]); ...
Read more

How to Change swipe Tab Title color in java Android -

-
by default, view pager(swipe tabs) tab title color white want change orange. can 1 me please or share if have tutorial. thanks... use style in styles.xml , assign style tab layout. <style name="mymaterialtheme.tablayout" parent="widget.design.tablayout"> <item name="tabindicatorcolor">@android:color/white</item> <item name="tabindicatorheight">3dp</item> <item name="tabtextappearance">@style/mymaterialtheme.tablayout.textappearance</item> <item name="tabselectedtextcolor">@android:color/white</item> <item name="android:background">@color/colorprimary</item> </style> <style name="mymaterialtheme.tablayout.textappearance" parent="textappearance.design.tab"> <item name="android:textsize">14sp</item> <item name="android:textcolor">@color/tab_text_inactive</item> ...
Read more

Using globs in Perl replace one liner in TCL script -

-
i want run 1 perl 1 liner in tcl script below: exec perl -i -pe {s/substring/replacing_string/g} testfile; this works fine. but, if want modify files below: exec perl -i -pe {s/substring/replacing_string/g} *; it gives me error message: can't open '*': no such file or directory. while executing exec perl -i -pe {s/substring/replacing_string/g} *; i tried bracing '*', did not solve problem. requesting help... assuming files a , b , , c present in current working directory, executing echo * in shell prints a b c . because shell command evaluator recognizes wildcard characters , splices in list of 0 or more file names wildcard expression found. tcl's command evaluator not recognize wildcard characters, passes them unsubstituted command invoked. if command can work wildcards so. exec command doesn't, means pass wildcard expression shell command named command string. testing this, get % exec echo * * because asked shell exe...
Read more