Typescript errors on initial build, fine on rebuild after editing `.ts` file

#1

I just checked out an older Ionic v3 project (Ionic Framework : ionic-angular 3.5.3, @ionic/app-scripts : 3.2.0) and noticed something strange:

The first build via ionic serve failed with error messages like this:

λ ionic serve                                                                                                                                         
> ionic-app-scripts serve --address 0.0.0.0 --port 8100 --livereload-port 35729 --dev-logger-port 53703 --nobrowser                                   
[app-scripts] [19:02:47]  ionic-app-scripts 3.2.0                                                                                                     
[app-scripts] [19:02:47]  watch started ...                                                                                                           
[app-scripts] [19:02:47]  build dev started ...                                                                                                       
[app-scripts] [19:02:47]  clean started ...                                                                                                           
[app-scripts] [19:02:47]  clean finished in 20 ms                                                                                                     
[app-scripts] [19:02:47]  copy started ...                                                                                                            
[app-scripts] [19:02:48]  deeplinks started ...                                                                                                       
[app-scripts] [19:02:48]  deeplinks finished in 383 ms                                                                                                
[app-scripts] [19:02:48]  transpile started ...                                                                                                       
[app-scripts] [19:03:02]  typescript: E:/Projects/.../src/pages/analysis/analysis.ts, line: 85                                  
[app-scripts]             Property 'padStart' does not exist on type 'string'.                                                                        
[app-scripts]       L84:  let _month = getMonth(day.datetime);                                                                                        
[app-scripts] [19:03:02]  typescript: E:/Projects/.../src/pages/analysis/analysis.ts, line: 132                                 
[app-scripts] [19:03:02]  typescript: E:/Projects/.../src/pages/analysis/analysis.ts, line: 133                                 
[app-scripts]       L85:  let month = (_month+1).toString().padStart(2, "0");                                                                         
[app-scripts]       L86:  let year_month = year + '-' + month ;                                                                                       
[app-scripts]             Property 'values' does not exist on type 'ObjectConstructor'.                                                               
[app-scripts]      L131:  // Graphs                                                                                                                   
[app-scripts]      L132:  this.barChart = this._createChart(this.barCanvas, 'bar', Object.keys(years), Object.values(years));                         
[app-scripts]      L133:  this.barCharta = this._createChart(this.barCanvasa, 'bar', Object.keys(anbieter_years), Object.values(anbieter_years));     
[app-scripts]             Property 'values' does not exist on type 'ObjectConstructor'.                                                               
[app-scripts]      L132:  this.barChart = this._createChart(this.barCanvas, 'bar', Object.keys(years), Object.values(years));                         
[app-scripts]      L133:  ta = this._createChart(this.barCanvasa, 'bar', Object.keys(anbieter_years), Object.values(anbieter_years));                 
[app-scripts]      L134:  this.barChart2 = this._createChart(this.barCanvas2, 'bar', Object.keys(year_months), Object.values(year_months));           
[app-scripts]             Property 'values' does not exist on type 'ObjectConstructor'.                                                               
[app-scripts]      L133:      this.barCharta = this._createChart(this.barCanvasa, 'bar', Object.keys(anbieter_years), Object.values(anbieter_years)); 
[app-scripts]      L134:  arChart2 = this._createChart(this.barCanvas2, 'bar', Object.keys(year_months), Object.values(year_months));                 
[app-scripts] [19:03:02]  typescript: E:/Projects/.../src/pages/analysis/analysis.ts, line: 134                                 
[app-scripts] [19:03:02]  typescript: E:/Projects/.../src/pages/analysis/analysis.ts, line: 167                                 
[app-scripts]             Property 'xAxes' does not exist on type '{ yAxes: { ticks: { beginAtZero: boolean; }; }[]; }'.                              
[app-scripts]      L166:  config.type = 'line';                                                                                                       
[app-scripts]      L167:  config.options.scales.xAxes = [{                                                                                            
[app-scripts]      L168:    type: 'time',   

[INFO] Development server running!

       Local: http://localhost:8100
       External: http://192.168.178.34:8100
       DevApp: stromzaehler@8100 on Lenovo-X1

       Use Ctrl+C to quit this process

[INFO] Browser window opened to http://localhost:8100!

[app-scripts] [19:03:02]  copy finished in 14.57 s
[app-scripts] [19:03:02]  watch ready in 14.84 s                                                                                                         

The app opened in the browser, but only showed a nicer view of the same error mesage.

But after I edited a .ts file of the project (just added a few spaces, no real changes), this happened:

[app-scripts] [19:07:31]  copy update started ...
[app-scripts] [19:07:31]  copy update finished in 129 ms
[app-scripts] [19:07:46]  build started ...
[app-scripts] [19:07:46]  deeplinks update started ...
[app-scripts] [19:07:46]  deeplinks update finished in 242 ms
[app-scripts] [19:07:46]  transpile update started ...
[app-scripts] [19:07:46]  transpile update finished in 149 ms
[app-scripts] [19:07:46]  webpack started ...
[app-scripts] [19:08:09]  webpack finished in 22.43 s
[app-scripts] [19:08:09]  sass started ...
[app-scripts] [19:08:16]  sass finished in 6.94 s
[app-scripts] [19:08:16]  build finished in 29.90 s

And now the app works perfectly fine!

Any idea what is going on here and how I can fix this?