Files
spectator/src/lib/metapixel/fbc.ts
2025-12-18 19:22:54 -08:00

89 lines
2.5 KiB
TypeScript
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
import log from 'loglevel';
export type EnsureFbcOptions = {
days?: number; // cookie lifetime, default 180
domain?: string; // optional cookie domain
sameSite?: 'Lax' | 'Strict' | 'None'; // default Lax
secure?: boolean; // default inferred from location.protocol === 'https:'
pixelLoaded?: boolean; // if true, skip manual set and let Pixel handle it
};
function getParam(name: string): string | undefined {
const params = new URLSearchParams(location.search);
const v = params.get(name);
return v || undefined;
}
function getCookie(name: string): string | undefined {
return document.cookie
.split('; ')
.find((c) => c.startsWith(name + '='))
?.split('=')[1];
}
function setCookie(
name: string,
value: string,
{
days = 180,
domain,
sameSite = 'Lax',
secure
}: Pick<EnsureFbcOptions, 'days' | 'domain' | 'sameSite' | 'secure'> = {}
) {
const d = new Date();
d.setTime(d.getTime() + days * 864e5);
const parts = [
`${name}=${encodeURIComponent(value)}`,
`expires=${d.toUTCString()}`,
'path=/',
`SameSite=${sameSite}`
];
if (domain) parts.push(`domain=${domain}`);
const isSecure = secure ?? location.protocol === 'https:';
if (isSecure) parts.push('Secure');
document.cookie = parts.join('; ');
}
function isValidFbc(value: string | undefined): boolean {
if (!value) return false;
// Expect "fb.1.<unix>.<fbclid>"
if (!value.startsWith('fb.1.')) return false;
const parts = value.split('.');
return parts.length >= 4 && /^\d+$/.test(parts[2]) && parts[3].length > 0;
}
/**
* Ensure _fbc cookie exists when landing URL contains fbclid.
* Call after consent. If pixelLoaded is true, it skips manual setting.
*/
export function ensureFbc(options: EnsureFbcOptions = {}) {
try {
const { pixelLoaded = false, ...cookieOpts } = options;
if (pixelLoaded) throw new Error('Pixel loaded, skipping manual _fbc set'); // Let the Pixel set _fbc if its active
const fbclid = getParam('fbclid');
if (!fbclid) throw new Error('No fbclid param present');
const existing = getCookie('_fbc');
if (isValidFbc(existing)) throw new Error('_fbc cookie already present and valid');
const ts = Math.floor(Date.now() / 1000);
const fbc = `fb.1.${ts}.${fbclid}`;
setCookie('_fbc', fbc, cookieOpts);
log.debug('[ensureFbc] Set _fbc cookie:', fbc);
} catch (e) {
log.debug('[ensureFbc]', (e as Error).message);
}
}
/**
* Helper to read both _fbp and _fbc for your CAPI payload.
*/
export function getFbpFbc(): { fbp?: string; fbc?: string } {
const fbp = getCookie('_fbp');
const fbc = getCookie('_fbc');
return { fbp, fbc };
}