store several inputs in localstorage

[Nicolas_14]

Hi everyone!

I'm just begining on JS so I think my code is not very good.
I'm trying to store the results of my game each time it ends.
unfortunately it doesn't work well all the time. Sometimes I have exactly what I want: one line per recording, sometimes I have tons of wrong datas and I can't find the reason why.
Here is my code so far:

     score = {
        name: name,
        maxTurns: maxTurns,
        lowestProbability: lowestProbability * 100 + '%',
        totalTurns: totalTurns,
        initialProbability: initialProbability,
        totalSuccess: totalSuccess,
        date: new Date().getTime() 
    }


    let localData = localStorage.getItem('score') + JSON.stringify(score);
    localStorage.setItem("score", localData);

thanks in advance for your help!