test/parallel/test-timers-ordering.js

// Copyright Joyent, Inc. and other Node contributors.
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// Flags: --expose-internals

'use strict';
require('../common');
const assert = require('assert');
const { getLibuvNow } = require('internal/timers');

const N = 30;

let last_i = 0;
let last_ts = 0;

function f(i) {
  if (i <= N) {
    // check order
    assert.strictEqual(i, last_i + 1, `order is broken: ${i} != ${last_i} + 1`);
    last_i = i;

    // check that this iteration is fired at least 1ms later than the previous
    const now = getLibuvNow();
    assert(now >= last_ts + 1,
           `current ts ${now} < prev ts ${last_ts} + 1`);
    last_ts = now;

    // schedule next iteration
    setTimeout(f, 1, i + 1);
  }
}
setTimeout(f, 1, 1);