fix(typescript): remove now-unneeded workaround for directives (#8422)

* fix(typescript): remove unneeded workaround for directives

* Add changelog entry

changelog_unreleased/typescript/pr-8422.md

@@ -0,0 +1,23 @@
+#### Parenthesize string literals to avoid interpreting as directives ([#8422](https://github.com/prettier/prettier/pull/8422) by [@thorn0](https://github.com/thorn0))
+
+Prettier wraps any string literal which is in statement position in parentheses because otherwise such strings would get interpreted as directives if they occurred at the top of a function or program, which can change the behavior of the program. It is not technically necessary to do this for strings which are not on the first line of a function or program. But doing so anyway is more consistent and can highlight bugs. See for example [this thread on twitter](https://twitter.com/dan_abramov/status/874601179334017024).
+
+Previously this didn't consistently work for the `typescript` parser. Only strings already wrapped in parentheses retained them.
+
+<!-- prettier-ignore -->
+```ts
+// Input
+f();
+'use foo';
+('use bar');
+
+// Prettier stable
+f();
+"use foo";
+("use bar");
+
+// Prettier master
+f();
+("use foo");
+("use bar");
+```

src/language-js/needs-parens.js

@@ -475,11 +475,7 @@ function needsParens(path, options) {
       if (
         typeof node.value === "string" &&
         parent.type === "ExpressionStatement" &&
-        // TypeScript workaround for https://github.com/JamesHenry/typescript-estree/issues/2
-        // See corresponding workaround in printer.js case: "Literal"
-        ((options.parser !== "typescript" && !parent.directive) ||
-          (options.parser === "typescript" &&
-            options.originalText.charAt(options.locStart(node) - 1) === "("))
+        !parent.directive
       ) {
         // To avoid becoming a directive
         const grandParent = path.getParentNode(1);

src/language-js/printer-estree.js

@@ -487,7 +487,7 @@ function printPathNoParens(path, options, print, args) {
     case "EmptyStatement":
       return "";
     case "ExpressionStatement":
-      // Detect Flow-parsed directives
+      // Detect Flow and TypeScript directives
       if (n.directive) {
         return concat([nodeStr(n.expression, options, true), semi]);
       }
@@ -1617,7 +1617,7 @@ function printPathNoParens(path, options, print, args) {
       return (n.bigint || n.extra.raw).toLowerCase();
     case "BooleanLiteral": // Babel 6 Literal split
     case "StringLiteral": // Babel 6 Literal split
-    case "Literal": {
+    case "Literal":
       if (n.regex) {
         return printRegex(n.regex);
       }
@@ -1631,18 +1631,7 @@ function printPathNoParens(path, options, print, args) {
       if (typeof n.value !== "string") {
         return "" + n.value;
       }
-      // TypeScript workaround for https://github.com/JamesHenry/typescript-estree/issues/2
-      // See corresponding workaround in needs-parens.js
-      const grandParent = path.getParentNode(1);
-      const isTypeScriptDirective =
-        options.parser === "typescript" &&
-        typeof n.value === "string" &&
-        grandParent &&
-        (grandParent.type === "Program" ||
-          grandParent.type === "BlockStatement");
-
-      return nodeStr(n, options, isTypeScriptDirective);
-    }
+      return nodeStr(n, options);
     case "Directive":
       return path.call(print, "value"); // Babel 6
     case "DirectiveLiteral":

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

@@ -82,6 +82,26 @@ printWidth: 80
 ================================================================================
 `;
 
+exports[`issue-7346.js format 1`] = `
+====================================options=====================================
+parsers: ["babel", "flow", "typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+('bar'); // parens should not be removed to avoid becoming a directive
+\`foo\`;
+'bar'; // parens should be added, see https://github.com/prettier/prettier/issues/7346#issuecomment-574823604
+'"';
+
+=====================================output=====================================
+("bar"); // parens should not be removed to avoid becoming a directive
+\`foo\`;
+("bar"); // parens should be added, see https://github.com/prettier/prettier/issues/7346#issuecomment-574823604
+('"');
+
+================================================================================
+`;
+
 exports[`last-line-0.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]

tests/js/directives/issue-7346.js

@@ -0,0 +1,4 @@
+('bar'); // parens should not be removed to avoid becoming a directive
+`foo`;
+'bar'; // parens should be added, see https://github.com/prettier/prettier/issues/7346#issuecomment-574823604
+'"';