index

Performance Benchmarks

Conversion performance

Measured on Node 22, Apple M2. Input: 1,000 random dates in range 1900-2076 CE.

Operation	UAQ calendar	FCNA calendar
d.toHijri()	~0.5 µs/call	~14 µs/call
d.iYear()	~0.5 µs/call	~14 µs/call
dayjs.fromHijri()	~0.6 µs/call	~15 µs/call
d.format('iD iMMMM iYYYY')	~1.2 µs/call	~15 µs/call

UAQ uses a precomputed lookup table (O(1) lookup). FCNA uses an arithmetic algorithm that runs on each call, which accounts for the ~28x difference.

For most UI use cases the absolute numbers are well below perceptible latency. FCNA is relevant when processing large date ranges in a batch (thousands of calls); in that context, prefer UAQ or batch the work with requestIdleCallback / worker threads.

Bundle size

The plugin adds minimal weight on top of Day.js.

Module	Min+gz
dayjs-hijri-plus (wrapper only)	~1.5 KB
hijri-core/uaq (peer dep, UAQ engine)	~5.3 KB
hijri-core/fcna (peer dep, FCNA engine)	~3.1 KB
dayjs (peer dep, separate)	~6.9 KB

Both hijri-core and dayjs-hijri-plus are tree-shakeable (named ESM exports). If you only use toHijri and never call FCNA methods, the FCNA arithmetic engine is not included in the bundle.

Reproducing the benchmarks

import dayjs from 'dayjs';
import hijri from 'dayjs-hijri-plus';

dayjs.extend(hijri);

const dates = Array.from({ length: 1000 }, (_, i) =>
  dayjs('1900-01-01').add(i * 26, 'day')
);

const start = performance.now();
for (const d of dates) {
  d.toHijri();
}
const elapsed = performance.now() - start;
console.log(`${(elapsed / dates.length * 1000).toFixed(1)} µs/call`);

Run with node --version >= 20. Results vary by machine and Node version.