JavaScript сочетает в себе словаря
var a = {};
a['fruit'] = "apple";
var b = {};
b['vegetable'] = "carrot";
var food = Object.assign({}, a, b);
console.log(food);
2Bowls
var a = {};
a['fruit'] = "apple";
var b = {};
b['vegetable'] = "carrot";
var food = Object.assign({}, a, b);
console.log(food);const target = { a: [1], b: [2] };
const source = { a: [2], c: [5] };
const returnedTarget = Object.assign(target, source);
for(var date in source)
target[date] = [...target[date] || [],...source[date]]
console.log(target);