csv2sheet readCSVContent (assumes CSV content, no parsing)

index.js

function readCSVContent(sheetsAPI, file, sheetName) {
  return new Promise((resolve, reject) => {
    const storage = new Storage();
    let fileContents = new Buffer('');
    let rows = [];
    storage
      .bucket(file.bucket)
      .file(file.name)
      .createReadStream()
      .on("error", function(err) {
        reject("The Storage API returned an error: " + err);
      })
      .on("data", function(chunk) {
        fileContents = Buffer.concat([fileContents, chunk]);
      })
      .on("end", function() {
        let content = fileContents.toString('utf8');
        console.log("CSV content read as string : " + content );
        resolve(content);
      });
  });
}