Update styleSheetSerializer with defensive check for null/undefined nodes

[shoosya]

Problem Description

Snapshot tests fail due to unguarded recursion when jest-style-components encounters a null or undefined child node.

PrettyFormatPluginError: Cannot read properties of undefined (reading 'children')
 ❯ getNodes ../node_modules/@cx/serializer/lib/styleSheetSerializer.js:10:12
 ❯ ../node_modules/@cx/serializer/lib/styleSheetSerializer.js:11:50
 ❯ getNodes ../node_modules/@cx/serializer/lib/styleSheetSerializer.js:11:31
 ❯ Object.serialize ../node_modules/@cx/serializer/lib/styleSheetSerializer.js:136:19
 ❯ printPlugin ../node_modules/@vitest/snapshot/node_modules/@vitest/pretty-format/dist/index.js:995:44
 ❯ format ../node_modules/@vitest/snapshot/node_modules/@vitest/pretty-format/dist/index.js:1146:16

Solution

• Add defensive guards for cases when node is null/undefined.
• Prevent snapshots from failing when node is not an iterable.

jest-styled-components/src/styleSheetSerializer.js

Line 5 in 7cc67f7

const getNodes = (node, nodes = []) => {

const getNodes = (node, nodes = []) => {
  if (!node || typeof node !== 'object') {
    return nodes;
  }

  nodes.push(node);

  if (node.children && typeof node.children === 'object') {
    try {
      Array.from(node.children).forEach((child) => getNodes(child, nodes));
    } catch (_) {
    }
  }

  return nodes;
};

Pull request: #451