Add powerline symbol test button to demo

demo/client.ts

@@ -159,6 +159,7 @@ if (document.location.pathname === '/test') {
   document.getElementById('htmlserialize').addEventListener('click', htmlSerializeButtonHandler);
   document.getElementById('custom-glyph').addEventListener('click', writeCustomGlyphHandler);
   document.getElementById('load-test').addEventListener('click', loadTest);
+  document.getElementById('powerline-symbol-test').addEventListener('click', powerlineSymbolTest);
   document.getElementById('add-decoration').addEventListener('click', addDecoration);
   document.getElementById('add-overview-ruler').addEventListener('click', addOverviewRuler);
 }
@@ -558,6 +559,28 @@ function loadTest() {
   });
 }
 
+function powerlineSymbolTest() {
+  function s(char: string): string {
+    return `${char} \x1b[7m${char}\x1b[0m  `;
+  }
+  term.write('\n\n\r');
+  term.writeln('Standard powerline symbols:');
+  term.writeln('      0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F');
+  term.writeln(`0xA_  ${s('\ue0a0')}${s('\ue0a1')}${s('\ue0a2')}`);
+  term.writeln(`0xB_  ${s('\ue0b0')}${s('\ue0b1')}${s('\ue0b2')}${s('\ue0b3')}`);
+  term.writeln('');
+  term.writeln('Powerline extra symbols:');
+  term.writeln('      0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F');
+  term.writeln(`0xA_                 ${s('\ue0a3')}`);
+  term.writeln(`0xB_                      ${s('\ue0b4')}${s('\ue0b5')}${s('\ue0b6')}${s('\ue0b7')}${s('\ue0b8')}${s('\ue0b9')}${s('\ue0ba')}${s('\ue0bb')}${s('\ue0bc')}${s('\ue0bd')}${s('\ue0be')}${s('\ue0bf')}`);
+  term.writeln(`0xC_  ${s('\ue0c0')}${s('\ue0c1')}${s('\ue0c2')}${s('\ue0c3')}${s('\ue0c4')}${s('\ue0c5')}${s('\ue0c6')}${s('\ue0c7')}${s('\ue0c8')}${s('\ue0c9')}${s('\ue0ca')}${s('\ue0cb')}${s('\ue0cc')}${s('\ue0cd')}${s('\ue0be')}${s('\ue0bf')}`);
+  term.writeln(`0xD_  ${s('\ue0d0')}${s('\ue0d1')}${s('\ue0d2')}     ${s('\ue0d4')}`);
+  term.writeln('');
+  term.writeln('Sample of nerd fonts icons:');
+  term.writeln('    nf-linux-apple (\\uF302) \uf302');
+  term.writeln('nf-mdi-github_face (\\uFbd9) \ufbd9');
+}
+
 function addDecoration() {
   term.options['overviewRulerWidth'] = 15;
   const marker = term.addMarker(1);

demo/index.html

@@ -69,6 +69,7 @@ <h3>Test</h3>
             <button id="dispose" title="This is used to testing memory leaks">Dispose terminal</button>
             <button id="custom-glyph" title="Write custom box drawing and block element characters to the terminal">Test custom glyphs</button>
             <button id="load-test" title="Write several MB of data to simulate a lot of data coming from the process">Load test</button>
+            <button id="powerline-symbol-test" title="Write powerline symbol characters to the terminal (\ue0a0+)">Powerline symbol test</button>
             <button id="add-decoration" title="Add a decoration to the terminal">Decoration</button>
             <button id="add-overview-ruler" title="Add an overview ruler to the terminal">Add Overview Ruler</button>
           </div>