removing unnecessary conditions and hardlines and cleaning up the doc…

…umentation

src/nodes/Conditional.js

@@ -1,15 +1,8 @@
 import { doc } from 'prettier';
 import { printSeparatedItem } from '../common/printer-helpers.js';
 
-const {
-  breakParent,
-  group,
-  hardline,
-  hardlineWithoutBreakParent,
-  ifBreak,
-  indent,
-  line
-} = doc.builders;
+const { group, hardline, hardlineWithoutBreakParent, ifBreak, indent, line } =
+  doc.builders;
 
 let groupIndex = 0;
 const experimentalTernaries = (node, path, print) => {
@@ -20,16 +13,11 @@ const experimentalTernaries = (node, path, print) => {
     node.trueExpression.type === 'Conditional' ||
     node.falseExpression.type === 'Conditional';
 
-  // If the current `Conditional` is nested in another `Conditional`'s
-  // `trueExpression`, we add a line without propagating the break group.
   // If the `conditionDoc` breaks into multiple lines, we add parentheses,
   // unless it already is a `TupleExpression`.
-  // This can only be done because we are sure that the `condition` must be a
-  // single `bool` value.
   const conditionDoc = path.call(print, 'condition');
   const conditionGroup = group(
     [
-      isNestedAsTrueExpression ? hardlineWithoutBreakParent : '',
       node.condition.type === 'TupleExpression'
         ? conditionDoc
         : ifBreak(['(', printSeparatedItem(conditionDoc), ')'], conditionDoc),
@@ -41,9 +29,10 @@ const experimentalTernaries = (node, path, print) => {
   groupIndex += 1;
 
   // If the `conditionGroup` breaks we force a new line to separate the
-  // `trueExpression` and `falseExpression`.
-  // In the case of `Conditional`, `VariableDeclarationStatement` and
-  // `ReturnStatement` we avoid propagating the group breaking.
+  // `trueExpression` and `falseExpression` following the "curious" ternaries
+  // format.
+  // We need a `hardlineWithoutBreakParent` because `hardline` doesn't play
+  // well with `ifBreak`. (See https://github.com/prettier/prettier/issues/15710)
   const expressionSeparator = ifBreak(hardlineWithoutBreakParent, line, {
     groupId: conditionGroup.id
   });
@@ -53,9 +42,7 @@ const experimentalTernaries = (node, path, print) => {
   // ternaries in the parent `Conditional`s.
   const trueExpressionDoc = printSeparatedItem(
     [
-      isNestedAsTrueExpression
-        ? hardlineWithoutBreakParent
-        : expressionSeparator,
+      isNestedAsTrueExpression ? hardline : expressionSeparator,
       path.call(print, 'trueExpression')
     ],
     { firstSeparator: '' }
@@ -64,27 +51,19 @@ const experimentalTernaries = (node, path, print) => {
   // We force a new line if current `Conditional` is nested or nests a
   // `Conditional`. Otherwise we add a normal separator.
   const falseExpressionDoc = group([
-    isNested || hasNestedConditional
-      ? hardlineWithoutBreakParent
-      : expressionSeparator,
+    isNested || hasNestedConditional ? hardline : expressionSeparator,
     ': ',
     path.call(print, 'falseExpression')
   ]);
 
   const document = group([
-    parent.type === 'TupleExpression' || parent.type === 'FunctionCall'
-      ? breakParent
-      : '',
     conditionGroup,
     trueExpressionDoc,
     falseExpressionDoc
   ]);
 
   return parent.type === 'VariableDeclarationStatement'
-    ? ifBreak(
-        indent([hasNestedConditional ? hardline : line, document]),
-        document
-      )
+    ? ifBreak(indent([line, document]), document)
     : document;
 };
 

src/parser.js

@@ -88,6 +88,8 @@ function parse(text, _parsers, options = _parsers) {
     },
     Conditional(ctx) {
       rearrangeConditional(ctx);
+      // We can remove parentheses only because we are sure that the
+      // `condition` must be a single `bool` value.
       while (
         ctx.condition.type === 'TupleExpression' &&
         !ctx.condition.isArray &&

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

@@ -367,11 +367,7 @@ contract Conditional {
         );
 
         // Conditional as a condition
-        (
-            foo ? 1 : bar
-        ) ?
-            3
-        : 4;
+        (foo ? 1 : bar) ? 3 : 4;
         (
             isCat() ? meow()
             : isDog() ? bark()