async-promise.js

async-promise.js

const fs = require('fs');

const readFileAsArray = function(file, cb = () => {}) {
    return new Promise((resolve, reject) => {
        fs.readFile(file, function(err, data) {
            if (err) {
                return reject(err)
                cb(err)
            }

            const lines = data.toString().trim().split('\n')
            resolve(lines)
            cb(null, lines)
        });

    });
}

readFileAsArray('./numbers')
    .then(lines => {
        const numbers = lines.map(Number);
        const oddNumbers = numbers.filter(number => number % 2 === 1)
        console.log('odd nums count', oddNumbers.length)
    })
    .catch(console.error)


    readFileAsArray('./numbers', (err, lines) => {
        if (err) throw err;

        const numbers = lines.map(Number);
        const oddNumbers = numbers.filter(number => number % 2 === 1)
        console.log('odd nums count', oddNumbers.length)

    })


    async function countOdd() {
        try {
            const lines = await readFileAsArray('./numbers')
            const numbers = lines.map(Number);
            const oddNumbers = numbers.filter(number => number % 2 === 1)
            console.log('odd nums count', oddNumbers.length)
        } catch(err) {
            console.error(err)
        }
    }

    countOdd()