first version

src/vote/vote.service.ts

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+import { Injectable } from '@nestjs/common';
+import { VoteCreateDTO } from './vote.dto';
+import { Vote } from './vote.entity';
+import { Repository } from 'typeorm';
+import { InjectRepository } from '@nestjs/typeorm';
+
+interface IAnswer {
+  question_id: string;
+  answer: string;
+}
+
+interface IVote {
+  answers: IAnswer[];
+}
+
+@Injectable()
+export class VoteService {
+  constructor(
+    @InjectRepository(Vote) private voteRepository: Repository<Vote>,
+  ) {}
+  async create(value: VoteCreateDTO) {
+    const vote = Object.entries(value).reduce<IVote>(
+      (acc, [question_id, a]) => {
+        const answer = String(a);
+        acc.answers.push({ question_id, answer });
+        return acc;
+      },
+      {
+        answers: [],
+      },
+    );
+    const voteEntity = this.voteRepository.create(vote);
+    await this.voteRepository.save(voteEntity);
+  }
+
+  async getResults() {
+    const all_votes = await this.voteRepository.find();
+    const compiled_results: { [question: string]: { [vote: string]: number } } =
+      {};
+
+    for (const vote of all_votes) {
+      for (const answer of vote.answers) {
+        if (!(answer.question_id in compiled_results)) {
+          compiled_results[answer.question_id] = {};
+        }
+        if (!(answer.answer in compiled_results[answer.question_id])) {
+          compiled_results[answer.question_id][answer.answer] = 0;
+        }
+        compiled_results[answer.question_id][answer.answer]++;
+      }
+    }
+    return compiled_results;
+  }
+}