const exams = [
    {
        "id": 1,
        "title": "Avaliação - Procedimento em Serras",
        "description": "Uma pequena descrição sobre a avaliação."
    },
    {
        "id": 3,
        "title": "Avaliação de Recuperação - Procedimento em Serras",
        "description": "Uma pequena descrição sobre a avaliação."
    }
];
 
const exam_score = [
    {
        "id": 4,
        "score": "0.00",
        "exam_id": 1
    }
];
 
 
const merged = exams.map((e) => ({
  ...e,
  exam_score: { ...exam_score.some(({ exam_id }) => exam_id === e.id) },
}));
 
console.log(merged);

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