vitaly-t

import {generatePrimes} from 'primes-generator';

// there are 1,270,607 primes in the first 20mln:
const iterator = generatePrimes({boost: 1_270_607});

let a, lastValue = 0, count = 0;
const start = Date.now();

do {
    a = iterator.next();

vitaly-t

function sieveOddPrimesTo(bufferLimit: number) {
    const lmti = (bufferLimit - 3) >> 1;
    const sz = (lmti >> 3) + 1;
    const cmpSts = new Uint8Array(sz);
    for (let i = 0; ; ++i) {
        const p = i + i + 3;
        const sqri = (i << 1) * (i + 3) + 3;
        if (sqri > lmti) {
            break;
        }

vitaly-t

/**
 * Drains the source observable till it completes, and then posts a new value-observable.
 */
function drain<T>(value: T | Observable<T> | (() => T | Observable<T>)) {
    const v = () => {
        const a = typeof value === 'function' ? value.call(null) : value;
        return a instanceof Observable ? a : of(a);
    }
    return s => defer(() => s.pipe(filter(_ => false), c => concat(c, v()))) as Observable<T>;
}

vitaly-t

Is there a regular expression to detect a valid regular expression?.

Deleted from StackOverflow by the author, because oddly, it got many downvotes.

---

Reflecting on this in 2016, in the way that things changed since...

The direct answer to the question is still the resounding NO, it is impossible to implement a regular expression to find all regular expressions in your code.

vitaly-t

const header = require('./db/header');

const promise = header.defPromise;
const options = {
    promiseLib: promise,
    noWarnings: true
};
const dbHeader = header(options);
const pgp = dbHeader.pgp;
const db = dbHeader.db;

vitaly-t

// Alternative/official approach to serializing BigInt:

BigInt.prototype.toJSON = function () {
    return `${this.toString()}n`;
};

vitaly-t

// Alternative/official approach to serializing BigInt:
BigInt.prototype.toJSON = function () {
    return `${this.toString()}n`;
};

vitaly-t

function parse(text) {
    return JSON.parse(text, (_, value) => {
        if (typeof value === 'string') {
            const m = value.match(/(-?\d+)n/);
            if (m && m[0] === value) {
                value = BigInt(m[1]);
            }
        }
        return value;
    });

vitaly-t

// Works the same as JSON.parse, but also handles BigInt type,
// by returning BigInt for each string that uses 123n format:
function parse(text) {
    return JSON.parse(text, (_, value) => {
        if (typeof value === 'string') {
            const m = value.match(/(-?\d+)n/);
            if (m && m[0] === value) {
                value = BigInt(m[1]);
            }
        }

vitaly-t

// Works the same as JSON.parse, but also handles BigInt type,
// by returning BigInt for each string that uses 123n format:

function parse(text) {
    return JSON.parse(text, (_, value) => {
        if (typeof value === 'string') {
            const m = value.match(/(-?\d+)n/);
            if (m && m[0] === value) {
                value = BigInt(m[1]);
            }