Get presigned upload url for S3 compatible with Uppy and Netlify Functions

sign.js

const AWS = require('aws-sdk')

const s3 = new AWS.S3({
  accessKeyId: process.env.AWS_KEY,
  secretAccessKey: process.env.AWS_SECRET,
  useAccelerateEndpoint: true
})

const getSignedUrlPromise = (operation, params) => {
  return new Promise((resolve, reject) => {
    return s3.getSignedUrl(operation, params, (err, url) => {
      return err ? reject(err) : resolve(url)
    })
  })
}

exports.handler = async (event, context) => {
  const key = event.queryStringParameters.key

  try {
    const url = await getSignedUrlPromise('putObject', {
      Bucket: process.env.S3_BUCKET,
      ContentType: 'image/jpeg',
      Key: key
    }).catch((err) => console.log(err))

    return {
      statusCode: 200,
      body: JSON.stringify({
        method: 'PUT',
        url: url,
        fields: []
      })
    }
  } catch (err) {
    console.log(err)

    return {
      statusCode: 500,
      body: 'NOT OK'
    }
  }
}