Some TypeScript code that I've use repeatedly

helpers.ts

const fs = require('fs');
const parseDomain = require("parse-domain");

function readJson(filename) {
    return JSON.parse(
        fs.readFileSync(filename)
    );
}

function getDomain(url) {
    let parsed = parseDomain(url);
    let host;
    try {
        return parsed.domain + "." + parsed.tld;
    } catch (e) {
        return;
    }    
}

function head(obj, num = 5) {
    let keys = Object.keys(obj)
    let out = {}
    for (let i in keys) {
        if (i >= num)
            break;
        let key = keys[i]
        out[key] = obj[key]
    }
    return out
}

function uniq(arr) {
    return Array.from(new Set(arr))
}