feat: added timestamp rfc3339 format with nanoseconds

docs/api.md

@@ -1414,6 +1414,7 @@ The `pino.stdTimeFunctions` object provides a very small set of common functions
 * `pino.stdTimeFunctions.unixTime`: Seconds since Unix epoch
 * `pino.stdTimeFunctions.nullTime`: Clears timestamp property (Used when `timestamp: false`)
 * `pino.stdTimeFunctions.isoTime`: ISO 8601-formatted time in UTC
+* `pino.stdTimeFunctions.isoTimeNano`: RFC 3339-formatted time in UTC with nanosecond precision
 
 * See [`timestamp` option](#opt-timestamp)
 

lib/time.js

@@ -8,4 +8,32 @@ const unixTime = () => `,"time":${Math.round(Date.now() / 1000.0)}`
 
 const isoTime = () => `,"time":"${new Date(Date.now()).toISOString()}"` // using Date.now() for testability
 
-module.exports = { nullTime, epochTime, unixTime, isoTime }
+const NS_PER_MS = 1_000_000n
+const NS_PER_SEC = 1_000_000_000n
+
+const startWallTimeNs = BigInt(Date.now()) * NS_PER_MS
+const startHrTime = process.hrtime.bigint()
+
+const isoTimeNano = () => {
+  const elapsedNs = process.hrtime.bigint() - startHrTime
+  const currentTimeNs = startWallTimeNs + elapsedNs
+
+  const secondsSinceEpoch = currentTimeNs / NS_PER_SEC
+  const nanosWithinSecond = currentTimeNs % NS_PER_SEC
+
+  const msSinceEpoch = Number(secondsSinceEpoch * 1000n + nanosWithinSecond / 1_000_000n)
+  const date = new Date(msSinceEpoch)
+
+  const year = date.getUTCFullYear()
+  const month = (date.getUTCMonth() + 1).toString().padStart(2, '0')
+  const day = date.getUTCDate().toString().padStart(2, '0')
+  const hours = date.getUTCHours().toString().padStart(2, '0')
+  const minutes = date.getUTCMinutes().toString().padStart(2, '0')
+  const seconds = date.getUTCSeconds().toString().padStart(2, '0')
+
+  return `,"time":"${year}-${month}-${day}T${hours}:${minutes}:${seconds}.${nanosWithinSecond
+    .toString()
+    .padStart(9, '0')}Z"`
+}
+
+module.exports = { nullTime, epochTime, unixTime, isoTime, isoTimeNano }

pino.d.ts

@@ -816,6 +816,10 @@ declare namespace pino {
             * Returns ISO 8601-formatted time in UTC
             */
         isoTime: TimeFn;
+        /*
+            * Returns RFC 3339-formatted time in UTC
+            */
+        isoTimeNano: TimeFn;
     };
 
     //// Exported functions

test/timestamp-nano.test.js

@@ -0,0 +1,35 @@
+'use strict'
+
+/* eslint no-prototype-builtins: 0 */
+
+const { test } = require('tap')
+const { sink, once } = require('./helper')
+
+test('pino.stdTimeFunctions.isoTimeNano returns RFC 3339 timestamps', async ({ equal }) => {
+  // Mock Date.now at module initialization time
+  const now = Date.now
+  Date.now = () => new Date('2025-08-01T15:03:45.000000000Z').getTime()
+
+  // Mock process.hrtime.bigint at module initialization time
+  const hrTimeBigint = process.hrtime.bigint
+  process.hrtime.bigint = () => 100000000000000n
+
+  const pino = require('../')
+
+  const opts = {
+    timestamp: pino.stdTimeFunctions.isoTimeNano
+  }
+  const stream = sink()
+
+  // Mock process.hrtime.bigint at invocation time, add 1 day to the timestamp
+  process.hrtime.bigint = () => 100000000000000n + 86400012345678n
+
+  const instance = pino(opts, stream)
+  instance.info('foobar')
+  const result = await once(stream, 'data')
+  equal(result.hasOwnProperty('time'), true)
+  equal(result.time, '2025-08-02T15:03:45.012345678Z')
+
+  Date.now = now
+  process.hrtime.bigint = hrTimeBigint
+})

test/timestamp.test.js

@@ -12,6 +12,7 @@ test('pino exposes standard time functions', async ({ ok }) => {
   ok(pino.stdTimeFunctions.unixTime)
   ok(pino.stdTimeFunctions.nullTime)
   ok(pino.stdTimeFunctions.isoTime)
+  ok(pino.stdTimeFunctions.isoTimeNano)
 })
 
 test('pino accepts external time functions', async ({ equal }) => {

test/types/pino-top-export.test-d.ts

@@ -22,6 +22,7 @@ expectType<LevelMapping>(levels);
 expectType<MultiStreamRes>(multistream(process.stdout));
 expectType<SerializedError>(stdSerializers.err({} as any));
 expectType<string>(stdTimeFunctions.isoTime());
+expectType<string>(stdTimeFunctions.isoTimeNano());
 expectType<string>(version);
 
 // Can't test against `unique symbol`, see https://github.com/SamVerschueren/tsd/issues/49

test/types/pino.test-d.ts

@@ -258,6 +258,10 @@ const withTimeFn = pino({
     timestamp: pino.stdTimeFunctions.isoTime,
 });
 
+const withRFC3339TimeFn = pino({
+    timestamp: pino.stdTimeFunctions.isoTimeNano,
+});
+
 const withNestedKey = pino({
     nestedKey: "payload",
 });