JSON output & exit codes

browserlane is built to be scripted. Two mechanisms make its output easy to consume from other programs: the global --json flag and meaningful exit codes.

The --json flag

--json is a global flag — append it to a command to get machine-readable output where the command produces data:

bl eval --json 'JSON.stringify({url: location.href, title: document.title})'

This pairs naturally with bl eval, which is the most common place you want a structured payload back. Combine it with --stdin for longer scripts:

bl eval --json --stdin <<'EOF'
const rows = [...document.querySelectorAll('table tbody tr')];
JSON.stringify(rows.map(r => {
  const cells = r.querySelectorAll('td');
  return { name: cells[0].textContent.trim(), price: cells[1].textContent.trim() };
}));
EOF

State checks return true / false

The bl is checks print a plain true or false, which is easy to branch on in a script:

bl is visible "h1"        # prints "true" or "false"
bl is enabled "button"
bl is checked "#agree"
bl is actionable ".cta"

if [ "$(bl is visible '.modal')" = "true" ]; then
  bl click ".modal .close"
fi

Exit codes for scripting

Some commands signal their result through the exit code so you can use them directly in shell conditionals — no output parsing required. The clearest example is bl is-installed:

bl is-installed   # exit 0 = Chrome + chromedriver present, exit 1 = missing

bl is-installed || bl install   # install Chrome only if it isn't already there

More generally, bl follows the usual convention: a command exits 0 on success and non-zero on failure. Chains stop on the first failure, so a sequence like the following won't take the screenshot if navigation fails:

bl go https://example.com && bl screenshot -o page.png

Related

• bl is, bl is-installed, and bl eval in the CLI reference.
• Auto-waiting vs. explicit waits — failures vs. timeouts.