Add a test for "foo as bar" casts.

[mprobst]

Summary

clang-format: [JS] unit tests for type aliases.

Spec:
https://github.com/Microsoft/TypeScript/blob/master/doc/spec.md#3.10

These are already handled correctly.

[mprobst]

• test, test name

[djasper]

Looks good.

unittests/Format/FormatTestJS.cpp

verifyFormat("class C {\n"
                "}");
   verifyFormat("class C {\n"
                "  private x(@A x: string) {}\n"
                "}");
   verifyFormat("class X {}\n"
                "class Y {}");
 }
 
+TEST_F(FormatTestJS, TypeAliases) {
+  verifyFormat("type X = number;\n"
+               "class C {}");
+  verifyFormat("type X<Y> = Z<Y>;");
+  verifyFormat("type X = {\n"
+               "  y: number\n"
+               "};\n"
+               "class C {}");
+}
+
 TEST_F(FormatTestJS, Modules) {
   verifyFormat("import SomeThing from 'some/module.js';");
   verifyFormat("import {X, Y} from 'some/module.js';");
   verifyFormat("import a, {X, Y} from 'some/module.js';");
   verifyFormat("import {VeryLongImportsAreAnnoying, VeryLongImportsAreAnnoying,"
                " VeryLongImportsAreAnnoying, VeryLongImportsAreAnnoying"
                "} from 'some/module.js';");
   verifyFormat("import {X, Y,} from 'some/module.js';");
verifyFormat("var x = `/*a`;\n"
                "var y =\n ` */ `;");
   // Escaped backtick.
   verifyFormat("var x = ` \\` a`;\n"
                "var y;",
                "var x = ` \\` a`;\n"
                "var y;");
 }
 
-TEST_F(FormatTestJS, CastSyntax) { verifyFormat("var x = <type>foo;"); }
+TEST_F(FormatTestJS, CastSyntax) {
+  verifyFormat("var x = <type>foo;");
+  verifyFormat("var x = foo as type;");
+}
 
 TEST_F(FormatTestJS, TypeArguments) {
   verifyFormat("class X<Y> {}");
   verifyFormat("new X<Y>();");
   verifyFormat("foo<Y>(a);");
   verifyFormat("var x: X<Y>[];");
   verifyFormat("class C extends D<E> implements F<G>, H<I> {}");
   verifyFormat("function f(a: List<any> = null) {}");