[OsamaAnsar]

structuredText puts a leading space on every block that follows a whitespace-only text node, which is what pretty-printed HTML produces.

parse('<div>\n  <h1>Title</h1>\n  <p>First para</p>\n  <p>Second <b>bold</b> para</p>\n  <ul>\n    <li>one</li>\n    <li>two</li>\n  </ul>\n</div>').structuredText
// before: " Title\n First para\n Second bold para\n one\n two"
// after:  "Title\nFirst para\nSecond bold para\none\ntwo"

parse('<p>a</p> <p>b</p>').structuredText   // before: "a\n b"   after: "a\nb"
parse('<p>a <br> b</p>').structuredText     // before: "a \n b"  after: "a\nb"

Cause: the whitespace-only branch in structuredText set prependWhitespace even when the current block was still empty, so the first text of the next block got a prefix. Block lines were also never trimmed, so a space before a <br> stayed as a trailing space.

Fix: only remember pending whitespace when the block already has content, and .trim() each line after the existing whitespace normalisation.

One behaviour change beyond the pretty-printed case: since lines are now trimmed, a single leading/trailing space inside a line is dropped for compact HTML too (<p> a</p> gave " a", now "a"; <p>a </p>b gave "a \nb", now "a\nb"). Output for inputs without such spaces is unchanged, and the existing structuredText tests pass untouched. I took that to be the same bug, but say so if you would rather keep it.

Tests: 4 added next to the existing #structuredText tests in test/tests/html.js (pretty-printed list/headings case, <p>a</p> <p>b</p>, <br>, and a guard that a single space between inline elements is kept). With only the src/ change reverted all 4 fail; with it they pass.

How I ran things: bun is not installed here, so I bundled src/index.ts with esbuild (css-select 5.2.2 and entities 8.0.0, as in bun.lock) and ran mocha on Node 22 against that bundle, skipping issues/280.js (it needs the published npm packages). main: 303 passing, 4 failing. This branch: 307 passing, same 4 failing. The 4 failures are artifacts of my setup, not of this change: the two Module Import tests and the two unclosed tag repair subprocess tests need ts-node / a built dist. tsc --noEmit is clean.

Not tested: bun run build / test:dist against a real dist, eslint, Node 24/26.