Fix missing trailing commas on flow generics (#1381)

src/printer.js

@@ -1864,6 +1864,7 @@ function genericPrintNoParens(path, options, print, args) {
               join(concat([",", line]), path.map(print, "params"))
             ])
           ),
+          ifBreak(shouldPrintComma(options, "all") ? "," : ""),
           softline,
           ">"
         ])

tests/flow_generic/__snapshots__/jsfmt.spec.js.snap

@@ -26,3 +26,68 @@ var X = {
 };
 
 `;
+
+exports[`break.js 2`] = `
+var X = {
+  perform: function<    
+     A, B, C, D, E, F, G,     
+     T: (a: A, b: B, c: C, d: D, e: E, f: F) => G // eslint-disable-line space-before-function-paren
+   >(     
+     method: T, scope: any,     
+     a: A, b: B, c: C, d: D, e: E, f: F,    
+   ): G {
+  }
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+var X = {
+  perform: function<
+    A,
+    B,
+    C,
+    D,
+    E,
+    F,
+    G,
+    T: (a: A, b: B, c: C, d: D, e: E, f: F) => G, // eslint-disable-line space-before-function-paren
+  >(method: T, scope: any, a: A, b: B, c: C, d: D, e: E, f: F): G {},
+};
+
+`;
+
+exports[`trailing.js 1`] = `
+type State = {
+  errors: Immutable.Map<
+    Ahohohhohohohohohohohohohohooh,
+    Fbt | Immutable.Map<ErrorIndex, Fbt>
+  >,
+  shouldValidate: boolean,
+};
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+type State = {
+  errors: Immutable.Map<
+    Ahohohhohohohohohohohohohohooh,
+    Fbt | Immutable.Map<ErrorIndex, Fbt>
+  >,
+  shouldValidate: boolean
+};
+
+`;
+
+exports[`trailing.js 2`] = `
+type State = {
+  errors: Immutable.Map<
+    Ahohohhohohohohohohohohohohooh,
+    Fbt | Immutable.Map<ErrorIndex, Fbt>
+  >,
+  shouldValidate: boolean,
+};
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+type State = {
+  errors: Immutable.Map<
+    Ahohohhohohohohohohohohohohooh,
+    Fbt | Immutable.Map<ErrorIndex, Fbt>,
+  >,
+  shouldValidate: boolean,
+};
+
+`;

tests/flow_generic/jsfmt.spec.js

@@ -1 +1,2 @@
 run_spec(__dirname);
+run_spec(__dirname, { trailingComma: 'all' });

tests/flow_generic/trailing.js

@@ -0,0 +1,7 @@
+type State = {
+  errors: Immutable.Map<
+    Ahohohhohohohohohohohohohohooh,
+    Fbt | Immutable.Map<ErrorIndex, Fbt>
+  >,
+  shouldValidate: boolean,
+};