Extract printAssignment, printBinaryishExpression, and `printComm…

…ent` (#9722)

src/language-js/print/assignment.js

@@ -0,0 +1,95 @@
+"use strict";
+
+const {
+  builders: { concat, line, group, indent },
+} = require("../../document");
+const {
+  hasLeadingOwnLineComment,
+  isBinaryish,
+  isMemberExpressionChain,
+  isStringLiteral,
+} = require("../utils");
+const { shouldInlineLogicalExpression } = require("./binaryish");
+
+function printAssignment(
+  leftNode,
+  printedLeft,
+  operator,
+  rightNode,
+  printedRight,
+  options
+) {
+  if (!rightNode) {
+    return printedLeft;
+  }
+
+  const printed = printAssignmentRight(
+    leftNode,
+    rightNode,
+    printedRight,
+    options
+  );
+
+  return group(concat([printedLeft, operator, printed]));
+}
+
+function printAssignmentExpression(path, options, print) {
+  const n = path.getValue();
+  return printAssignment(
+    n.left,
+    path.call(print, "left"),
+    concat([" ", n.operator]),
+    n.right,
+    path.call(print, "right"),
+    options
+  );
+}
+
+function printVariableDeclarator(path, options, print) {
+  const n = path.getValue();
+  return printAssignment(
+    n.id,
+    path.call(print, "id"),
+    " =",
+    n.init,
+    n.init && path.call(print, "init"),
+    options
+  );
+}
+
+function printAssignmentRight(leftNode, rightNode, printedRight, options) {
+  if (hasLeadingOwnLineComment(options.originalText, rightNode)) {
+    return indent(concat([line, printedRight]));
+  }
+
+  const canBreak =
+    (isBinaryish(rightNode) && !shouldInlineLogicalExpression(rightNode)) ||
+    (rightNode.type === "ConditionalExpression" &&
+      isBinaryish(rightNode.test) &&
+      !shouldInlineLogicalExpression(rightNode.test)) ||
+    rightNode.type === "StringLiteralTypeAnnotation" ||
+    (rightNode.type === "ClassExpression" &&
+      rightNode.decorators &&
+      rightNode.decorators.length) ||
+    ((leftNode.type === "Identifier" ||
+      isStringLiteral(leftNode) ||
+      leftNode.type === "MemberExpression") &&
+      (isStringLiteral(rightNode) || isMemberExpressionChain(rightNode)) &&
+      // do not put values on a separate line from the key in json
+      options.parser !== "json" &&
+      options.parser !== "json5") ||
+    rightNode.type === "SequenceExpression";
+
+  if (canBreak) {
+    return group(indent(concat([line, printedRight])));
+  }
+
+  return concat([" ", printedRight]);
+}
+
+module.exports = {
+  printVariableDeclarator,
+  printAssignmentExpression,
+  printAssignment,
+  printAssignmentRight,
+};