Google Apps Script how detect typeof blob?

Question

var data = Utilities.newBlob("THis is blob data", MimeType.PLAIN_TEXT, 'test.txt');

if (  ?? ) then Logger.log('yes, this is blob') ;

How to detect data is blob? (not object)

instanceof Blob
// or
instanceof BlobSource

Result: ReferenceError: Blob or BlobSource is not defined

instanceof GoogleAppsScript.Base.Blob;
// ReferenceError: `GoogleAppsScript` is not defined

typeof data
// result: object

Object.prototype.toString.call(data);
// result: [object Object]

And/or `Object.prototype.toString.call(instance) === "[object Blob]"` if the `name` property isn't supported (GAS has a *really* old JS engine, though I hear it's getting updated). — T.J. Crowder, Aug 05 '21 at 11:25
`Object.prototype.toString.call(data);` result is `[object Object]` — Hasanudin H. Syafaat, Aug 05 '21 at 11:29

score 5 · Accepted Answer · answered Aug 05 '21 at 12:27

5

Try using duck typing:

if (typeof data.copyBlob === 'function')
{
  // it's probably a blob
  console.log('yep');
}

Reference: Class Blob

answered Aug 05 '21 at 12:27

Kos

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Looks like the best solution indeed ;) I would just wrap it in a function like this: `const isBlob = obj => 'function' === obj.copyBlob` – Dmitry Kostyuk Aug 05 '21 at 12:54

Google Apps Script how detect typeof blob?

1 Answers1