Remove isLineNext (#10304)

* Replace `isLineNext` with `isLineOrHardlineOrSoftline`

* Remove `isLineNext`

* Use `isEmptyStringOrAnyLine`

* Update condition

src/document/doc-utils.js

@@ -104,19 +104,6 @@ function findInDoc(doc, fn, defaultValue) {
   return result;
 }
 
-function isLineNextFn(doc) {
-  if (typeof doc === "string") {
-    return false;
-  }
-  if (doc.type === "line") {
-    return true;
-  }
-}
-
-function isLineNext(doc) {
-  return findInDoc(doc, isLineNextFn, false);
-}
-
 function willBreakFn(doc) {
   if (doc.type === "group" && doc.break) {
     return true;
@@ -379,7 +366,6 @@ module.exports = {
   isConcat,
   getDocParts,
   willBreak,
-  isLineNext,
   traverseDoc,
   findInDoc,
   mapDoc,

src/language-js/print/jsx.js

@@ -14,7 +14,7 @@ const {
     lineSuffixBoundary,
     join,
   },
-  utils: { willBreak, isLineNext },
+  utils: { willBreak },
 } = require("../../document");
 
 const { getLast, getPreferredQuote } = require("../../common/util");
@@ -32,6 +32,9 @@ const {
 const pathNeedsParens = require("../needs-parens");
 const { willPrintOwnComments } = require("../comments");
 
+const isEmptyStringOrAnyLine = (doc) =>
+  doc === "" || doc === line || doc === hardline || doc === softline;
+
 /**
  * @typedef {import("../../common/ast-path")} AstPath
  * @typedef {import("../types/estree").Node} Node
@@ -175,18 +178,15 @@ function printJsxElementInternal(path, options, print) {
   }
 
   // Trim trailing lines (or empty strings)
-  while (
-    children.length > 0 &&
-    (!getLast(children) || isLineNext(getLast(children)))
-  ) {
+  while (children.length > 0 && isEmptyStringOrAnyLine(getLast(children))) {
     children.pop();
   }
 
   // Trim leading lines (or empty strings)
   while (
-    children.length > 0 &&
-    (!children[0] || isLineNext(children[0])) &&
-    (!children[1] || isLineNext(children[1]))
+    children.length > 1 &&
+    isEmptyStringOrAnyLine(children[0]) &&
+    isEmptyStringOrAnyLine(children[1])
   ) {
     children.shift();
     children.shift();