TypeScript: Support a TS 3.9 breaking change for Optional Chaining an…

…d Non-Null Assertions (#8450) * Suuport improvement optional chaining ergonomics * Add changelog * Fix reviewed points
prettier · May 31, 2020 · 3fc7579 · 3fc7579
1 parent ffceb60
commit 3fc7579
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diff --git a/changelog_unreleased/typescript/pr-8450.md b/changelog_unreleased/typescript/pr-8450.md
@@ -0,0 +1,16 @@
+#### Support TypeScript 3.9 breaking change for Optional Chaining and Non-Null Assertions ([#8450](https://github.com/prettier/prettier/pull/8450) by [@sosukesuzuki](https://github.com/sosukesuzuki))
+
+See https://devblogs.microsoft.com/typescript/announcing-typescript-3-9/#breaking-changes
+
+<!-- prettier-ignore -->
+```ts
+// Input
+(a?.b)!.c;
+
+// Prettier stable
+a?.b!.c;
+
+// Prettier master
+(a?.b)!.c;
+
+```
diff --git a/src/language-js/needs-parens.js b/src/language-js/needs-parens.js
@@ -625,15 +625,20 @@ function needsParens(path, options) {
       }
 
     case "OptionalMemberExpression":
-    case "OptionalCallExpression":
+    case "OptionalCallExpression": {
+      const parentParent = path.getParentNode(1);
       if (
         (parent.type === "MemberExpression" && name === "object") ||
         ((parent.type === "CallExpression" ||
           parent.type === "NewExpression") &&
-          name === "callee")
+          name === "callee") ||
+        (parent.type === "TSNonNullExpression" &&
+          parentParent.type === "MemberExpression" &&
+          parentParent.object === parent)
       ) {
         return true;
       }
+    }
     // fallthrough
     case "CallExpression":
     case "MemberExpression":

diff --git a/tests/typescript/non-null/__snapshots__/jsfmt.spec.js.snap b/tests/typescript/non-null/__snapshots__/jsfmt.spec.js.snap
@@ -32,6 +32,54 @@ foo!.bar().baz().what();
 ================================================================================
 `;
 
+exports[`optional-chain.ts format 1`] = `
+====================================options=====================================
+parsers: ["typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+a?.b!.c;
+a?.b!.c.d;
+a?.b.c!.d;
+a!.b?.c;
+a?.b!?.c;
+a?.b!.c?.c;
+(a?.b!).c;
+(a?.b)!.c;
+
+a?.().b!.c;
+a?.().b!.c.d;
+a?.().b.c!.d;
+a?.().b!?.c;
+a?.().b!.c?.c;
+(a?.().b!).c;
+(a?.().b)!.c;
+
+(a?.b)![c?.d!]
+
+=====================================output=====================================
+a?.b!.c;
+a?.b!.c.d;
+a?.b.c!.d;
+a!.b?.c;
+a?.b!?.c;
+a?.b!.c?.c;
+(a?.b)!.c;
+(a?.b)!.c;
+
+a?.().b!.c;
+a?.().b!.c.d;
+a?.().b.c!.d;
+a?.().b!?.c;
+a?.().b!.c?.c;
+(a?.().b)!.c;
+(a?.().b)!.c;
+
+(a?.b)![c?.d!];
+
+================================================================================
+`;
+
 exports[`parens.ts format 1`] = `
 ====================================options=====================================
 parsers: ["typescript"]

diff --git a/tests/typescript/non-null/optional-chain.ts b/tests/typescript/non-null/optional-chain.ts
@@ -0,0 +1,18 @@
+a?.b!.c;
+a?.b!.c.d;
+a?.b.c!.d;
+a!.b?.c;
+a?.b!?.c;
+a?.b!.c?.c;
+(a?.b!).c;
+(a?.b)!.c;
+
+a?.().b!.c;
+a?.().b!.c.d;
+a?.().b.c!.d;
+a?.().b!?.c;
+a?.().b!.c?.c;
+(a?.().b!).c;
+(a?.().b)!.c;
+
+(a?.b)![c?.d!]