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let array = [{"id":"1","name":"name","categories":[{"subid":"10","name":"name"},{"subid":"11","name":"name"}]},{"id":"2","name":"name","categories":[{"subid":"20","name":"name"},{"subid":"21","name":"name"}]}]
let result = array.map(({id, categories, rest}) => ({
rest, id, categories: categories.map((o) => ({o, id}))
}))
console.log(result)
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