JSFiddle - React, Tailwind, and code Playground

JavaScript

var things = [
    {
        id: "12345",
        name: "Bryan"
    },
    {
        id: "55555",
        name: "Justin"
    }
];

function createHashByProperty(arr, propertyName) {
    var hash = {};
    for (var i = 0, count = arr.length; i < count; i++) {
        var element = arr[i];
        hash[element[propertyName]] = element;
    }
    return hash;
}

for (var i = 0; i < things.length; i++) {
    console.log('Before: ', things[i].name);
}

var hash = createHashByProperty(things, 'id');

hash['55555'].name = 'Mike'; // Was 'Justin'
hash['12345'].name = 'Brian'; // Was 'Bryan'

for (var i2 = 0; i2 < things.length; i2++) {
    console.log('After: ', things[i2].name);
}