brexInterviewQuestion.js

const input = `
timestamp="Wed Jun 19 09:35:36 PDT 2019" message="test 10" id=10 field_1="test 10" field_6="test 1"
timestamp="Wed Jun 19 09:35:37 PDT 2019" message="test 4" id=4 field_2="test 4"
timestamp="Wed Jun 19 09:35:38 PDT 2019" message="test 2" id=3 field_3="test 2" field_9="test 23"
timestamp="Wed Jun 19 09:35:39 PDT 2019" message="test 3" id=2 field_4="test 3"
timestamp="Wed Jun 19 09:35:40 PDT 2019" message="test 4" id=1 field_5="test 4"
timestamp="Wed Jun 19 09:35:37 PDT 2019" message="test 5" id=5 field_3="test 10"
timestamp="Wed Jun 19 09:35:40 PDT 2019" message="test 6" id=6 field_1="test 5"
`

const separateValues = (input) => {
    const regex = /(["'])(?:(?=(\\?))\2.)*?\1/g
    let arrayOfStringValues = input.match(regex);
    const keyValuePairsArray = [];
    arrayOfStringValues.forEach(string => {
        if(nonStringValuesExist(string, input)) {
            input = input.trim().split(' ')
            keyValuePairsArray.push(input.shift());
            input = input.join(' ')
        }
        const lengthOfString = string.length;
        const stringStartIndex = input.indexOf(string);
        const keyValuePairs = input.split('').splice(0, stringStartIndex+lengthOfString).join('');
        input = input.split('')
        input.splice(0, stringStartIndex+lengthOfString)
        input = input.join('')

        keyValuePairsArray.push(keyValuePairs);
    })
    return keyValuePairsArray
}

const nonStringValuesExist = (string, input) => {
    const lengthOfString = string.length;
    const stringStartIndex = input.indexOf(string);
    const testThis = input.slice(0, stringStartIndex+lengthOfString).trim();
    if(testThis.split('=').length > 2){
        return true;
    }
}

const createObj = (keyValuePairs) => {
    const obj = {};
    keyValuePairs.forEach(keyValuePair => {
        const splitValues = keyValuePair.trim().split("=");
        const key = splitValues.shift();
        const value = splitValues.join('');
        obj[key] = value;
    })
    return obj;
}

const getKeys = (keyValuePairs) => {
    const keys = [];
    keyValuePairs.forEach(keyValuePair => {
        Object.keys(keyValuePair).filter(kvp => !!kvp).forEach(key => {
            if (keys.indexOf(key) === -1) {
                keys.push(key);
            }
        })
    })
    return keys;
}

const compileCsv = (allKeys, keyValuePairs) => {
    let finalString = allKeys.join(',');
    keyValuePairs.sort((a, b) => a.id - b.id).forEach(keyValuePair => {
        const formattedData = allKeys.map(k => {
            if (keyValuePair[k]) {
                return `${keyValuePair[k]}`
            }
        })
        finalString = finalString.concat('\n', formattedData)
    })
    return finalString;
};

const main = (input) => {
    const splitInputsByNewLine = input.split('\n').filter(inp => !!inp);
    const arrayOfKeyValuePairs = splitInputsByNewLine.map(splitInput => {
        return createObj(separateValues(splitInput));
    })
    return compileCsv(getKeys(arrayOfKeyValuePairs), arrayOfKeyValuePairs)
}

console.log(main(input));