clang-format: [JS] strict prop init annotation.

[mprobst]

Summary

TypeScript uses the ! token for strict property initialization
assertions, as in:

class X {
  strictPropAsserted!: string;
}

Previously, clang-format would wrap between the ! and the : for
overly long lines. This patch fixes that by generally preventing the
wrap in that location.

[mprobst]

fix typo in test

lib/Format/TokenAnnotator.cpp

if (LBrace &&
       // detecting and breaking before the next entry in the parent submessage.
       if (Left.ParameterCount == 0)
         return true;
       // However, if this submessage is the first entry in its parent
       // submessage, Left.ParameterCount might be 1 in some cases.
       // We deal with this case later by detecting an entry
       // following a closing paren of this submessage.
     }
-    
     // If this is an entry immediately following a submessage, it will be
     // preceded by a closing paren of that submessage, like in:
     //     left---.  .---right
     //            v  v
     // sub: { ... } key: value
     // If there was a comment between `}` an `key` above, then `key` would be
     // put on a new line anyways.
     if (Left.isOneOf(tok::r_brace, tok::greater, tok::r_square))
if (Right.NestingLevel == 0 &&
         (Left.Tok.getIdentifierInfo() ||
          Left.isOneOf(tok::r_square, tok::r_paren)) &&
         Right.isOneOf(tok::l_square, tok::l_paren))
       return false; // Otherwise automatic semicolon insertion would trigger.
     if (Left.is(TT_JsFatArrow) && Right.is(tok::l_brace))
       return false;
     if (Left.is(TT_JsTypeColon))
       return true;
+    // Don't wrap between ":" and "!" of a strict prop init ("field!: type;").
+    if (Left.is(tok::exclaim) && Right.is(tok::colon))
+      return false;
     if (Right.is(Keywords.kw_is))
       return false;
     if (Left.is(Keywords.kw_in))
       return Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None;
     if (Right.is(Keywords.kw_in))
       return Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None;
     if (Right.is(Keywords.kw_as))
       return false; // must not break before as in 'x as type' casts

unittests/Format/FormatTestJS.cpp

verifyFormat("class X {\n"
                "}");
   verifyFormat("@Component({\n"
                "  moduleId: module.id,\n"
                "})\n"
                "class SessionListComponent implements OnDestroy, OnInit {\n"
                "}");
 }
 
+TEST_F(FormatTestJS, StrictPropInitWrap) {
+  const FormatStyle &Style = getGoogleJSStyleWithColumns(22);
+  verifyFormat("class X {\n"
+               "  strictPropInitField!:\n"
+               "       string;\n"
+               "}",
+               Style);
+}
+
 TEST_F(FormatTestJS, InterfaceDeclarations) {
   verifyFormat("interface I {\n"
                "  x: string;\n"
                "  enum: string[];\n"
                "  enum?: string[];\n"
                "}\n"
                "var y;");
   // Ensure that state is reset after parsing the interface.