NestingIdentLeadingBraces.html | Explore in Territory

<!DOCTYPE html>
<script src="../resources/runner.js"></script>
<script src="./resources/utils.js"></script>
<script>
const DECLARATIONS = 400;
const TRAILING_TOKENS_PER_DECLARATION = 1000;

// Makes many (invalid) width-declarations where {} appears at the start of
// the the value, with lots of trailing tokens after.
function makeStyle() {
  let rules = [];

  for (let i = 0; i < DECLARATIONS; i++) {
    rules.push(`width: {}
      ${[...Array(TRAILING_TOKENS_PER_DECLARATION).keys()]
          .map(x => `foo${x}`).join(' ')}
    ;`);
  }

  return `
    div {
      ${rules.join('\n')}
    }
  `
}

let globalCounter = 0;
const stylesheetText = makeStyle();
let stylesheet = new CSSStyleSheet();

PerfTestRunner.measureTime({
    description: 'Many invalid width declarations with braces at the start',
    run: () => {
      // This is a parsing test: we don't care about style recalc.
      // We append a rule based on globalCounter to prevent caching
      // on the stylesheet string.
      stylesheet.replaceSync(stylesheetText + `\n .b${globalCounter++} {}`);
    }
});

</script>

chromium/third_party/blink/perf_tests/css/NestingIdentLeadingBraces.html