Improve formatting for assignment its left can break (#15547)

changelog_unreleased/javascript/15547.md

@@ -0,0 +1,18 @@
+#### Improve formatting for assignment its left can break (#15547 by @sosukesuzuki)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+params["redirectTo"] =
+  `${window.location.pathname}${window.location.search}${window.location.hash}`;
+
+// Prettier stable
+params[
+  "redirectTo"
+] = `${window.location.pathname}${window.location.search}${window.location.hash}`;
+
+// Prettier main
+params["redirectTo"] =
+  `${window.location.pathname}${window.location.search}${window.location.hash}`;
+
+```

src/language-js/print/assignment.js

@@ -141,11 +141,13 @@ function chooseLayout(path, options, print, leftDoc, rightPropertyName) {
     return "never-break-after-operator";
   }
 
+  const canBreakLeftDoc = canBreak(leftDoc);
+
   if (
     isComplexDestructuring(node) ||
     isComplexTypeAliasParams(node) ||
     hasComplexTypeAnnotation(node) ||
-    (isArrowFunctionVariableDeclarator(node) && canBreak(leftDoc))
+    (isArrowFunctionVariableDeclarator(node) && canBreakLeftDoc)
   ) {
     return "break-lhs";
   }
@@ -163,12 +165,13 @@ function chooseLayout(path, options, print, leftDoc, rightPropertyName) {
   }
 
   if (
-    hasShortKey ||
-    rightNode.type === "TemplateLiteral" ||
-    rightNode.type === "TaggedTemplateExpression" ||
-    rightNode.type === "BooleanLiteral" ||
-    isNumericLiteral(rightNode) ||
-    rightNode.type === "ClassExpression"
+    !canBreakLeftDoc &&
+    (hasShortKey ||
+      rightNode.type === "TemplateLiteral" ||
+      rightNode.type === "TaggedTemplateExpression" ||
+      rightNode.type === "BooleanLiteral" ||
+      isNumericLiteral(rightNode) ||
+      rightNode.type === "ClassExpression")
   ) {
     return "never-break-after-operator";
   }

tests/format/angular/angular/__snapshots__/jsfmt.spec.js.snap

@@ -1147,7 +1147,8 @@ printWidth: 1
   (target)="
     a[
       b
-    ] = 1
+    ] =
+      1
   "
   (target)="
     (a) // hello

tests/format/js/assignment/__snapshots__/jsfmt.spec.js.snap

@@ -784,6 +784,33 @@ const { _id: id3 } =
 ================================================================================
 `;
 
+exports[`issue-15534.js format 1`] = `
+====================================options=====================================
+parsers: ["babel", "flow", "typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+params["redirectTo"] = \`\${window.location.pathname}\${window.location.search}\${window.location.hash}\`;
+
+params["redirectTo"]["codePointAt"]["name"] =
+  \`\${window.location.pathname}\${window.location.search}\${window.location.hash}\`;
+
+params.redirectTo.bar.bar.ba.barab["foo"].abr =
+  \`\${window.location.pathname}\${window.location.search}\${window.location.hash}\`;
+
+=====================================output=====================================
+params["redirectTo"] =
+  \`\${window.location.pathname}\${window.location.search}\${window.location.hash}\`;
+
+params["redirectTo"]["codePointAt"]["name"] =
+  \`\${window.location.pathname}\${window.location.search}\${window.location.hash}\`;
+
+params.redirectTo.bar.bar.ba.barab["foo"].abr =
+  \`\${window.location.pathname}\${window.location.search}\${window.location.hash}\`;
+
+================================================================================
+`;
+
 exports[`lone-arg.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]

tests/format/js/assignment/issue-15534.js

@@ -0,0 +1,7 @@
+params["redirectTo"] = `${window.location.pathname}${window.location.search}${window.location.hash}`;
+
+params["redirectTo"]["codePointAt"]["name"] =
+  `${window.location.pathname}${window.location.search}${window.location.hash}`;
+
+params.redirectTo.bar.bar.ba.barab["foo"].abr =
+  `${window.location.pathname}${window.location.search}${window.location.hash}`;