Which Runs Faster?

let sum = 0;
for(let i = 0; i < 1000; i++) {
    let a = {};
    for(let i = 0; i < 19; i++) {
        a["a" + (i + 0.1)] = Math.random();
    }
    for(const prop in a) {
        sum += a[prop];
    }
}
let sum = 0;
for(let i = 0; i < 1000; i++) {
    let a = {};
    for(let i = 0; i < 19; i++) {
        a["a" + Math.random()] = i + 0.1;
    }
    for(const prop in a) {
        sum += a[prop];
    }
}
https://jsbench.me/74ku49o067/1

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