Support for Flow's Indexed Access type (#10594)

changelog_unreleased/flow/10594.md

@@ -0,0 +1,15 @@
+#### Support for Flow's indexed access type (#10594 by @gkz)
+
+Support for Flow's indexed access type.
+
+<!-- prettier-ignore -->
+```js
+// Input
+const x: Obj['foo'] = 1;
+
+// Prettier stable
+// Error: unsupported node type "IndexedAccessType"
+
+// Prettier main
+const x: Obj["foo"] = 1;
+```

src/language-js/print/flow.js

@@ -10,6 +10,7 @@ const {
   printUnionType,
   printFunctionType,
   printTupleType,
+  printIndexedAccessType,
 } = require("./type-annotation");
 const { printInterface } = require("./interface");
 const { printTypeParameters } = require("./type-parameters");
@@ -81,6 +82,8 @@ function printFlow(path, options, print) {
         print("id"),
         printTypeParameters(path, options, print, "typeParameters"),
       ];
+    case "IndexedAccessType":
+      return printIndexedAccessType(path, options, print);
     // Type Annotations for Facebook Flow, typically stripped out or
     // transformed away before printing.
     case "TypeAnnotation":

src/language-js/print/type-annotation.js

@@ -297,6 +297,11 @@ function printTupleType(path, options, print) {
   ]);
 }
 
+// `TSIndexedAccessType` and `IndexedAccessType`
+function printIndexedAccessType(path, options, print) {
+  return [print("objectType"), "[", print("indexType"), "]"];
+}
+
 module.exports = {
   printOpaqueType,
   printTypeAlias,
@@ -304,5 +309,6 @@ module.exports = {
   printUnionType,
   printFunctionType,
   printTupleType,
+  printIndexedAccessType,
   shouldHugType,
 };

src/language-js/print/typescript.js

@@ -47,6 +47,7 @@ const {
   printUnionType,
   printFunctionType,
   printTupleType,
+  printIndexedAccessType,
 } = require("./type-annotation");
 
 function printTypescript(path, options, print) {
@@ -280,7 +281,7 @@ function printTypescript(path, options, print) {
     case "TSLiteralType":
       return print("literal");
     case "TSIndexedAccessType":
-      return [print("objectType"), "[", print("indexType"), "]"];
+      return printIndexedAccessType(path, options, print);
     case "TSConstructSignatureDeclaration":
     case "TSCallSignatureDeclaration":
     case "TSConstructorType": {

tests/flow/indexed-access/__snapshots__/jsfmt.spec.js.snap

@@ -0,0 +1,16 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`indexed-access.js - {"trailingComma":"all"} format 1`] = `
+====================================options=====================================
+parsers: ["flow"]
+printWidth: 80
+trailingComma: "all"
+                                                                                | printWidth
+=====================================input======================================
+const x: Obj['bar'] = 1;
+
+=====================================output=====================================
+const x: Obj["bar"] = 1;
+
+================================================================================
+`;

tests/flow/indexed-access/indexed-access.js

@@ -0,0 +1 @@
+const x: Obj['bar'] = 1;

tests/flow/indexed-access/jsfmt.spec.js

@@ -0,0 +1 @@
+run_spec(__dirname, ["flow"], { trailingComma: "all" });