所以我找到了我问题的答案。
首先，我发现我需要将scalar Upload添加到typeDefs。
然后，我需要为Upload添加一个解析器，如下所示：

const { GraphQLUpload } = require('graphql-upload');

const server = new ApolloServer({
  resolvers: {
    Upload: GraphQLUpload,
  }
})

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然后在我的解析器中，这是我必须做的：

// this is a utility function to promisify the stream and store the image in a buffer, which then is passed to sharp
const streamToBuffer = (stream) => {
    const chunks = [];
    return new Promise((resolve, reject) => {
        stream.on('data', (chunk) => chunks.push(Buffer.from(chunk)));
        stream.on('error', (err) => reject(err));
        stream.on('end', () => resolve(Buffer.concat(chunks)));
    })
}

const Mutation = {
    createImage: async (_, { data }) => {
        const { file } = data
        const { createReadStream } = await file

        const imageBuffer = await streamToBuffer(createReadStream())

        const sharpImage = sharp(imageBuffer)
    }
}

型

Apollo建议使用签名URL，而不是通过mutations上传文件。https://www.apollographql.com/blog/backend/file-uploads/file-upload-best-practices/
这是由于CSRF风险和性能影响，特别是当应用扩展时。对于正确处理CSRF风险的应用，通过突变上传文件应该是可以的。