I would need something like this:
var docDefinition = {
content: [blob]
}
pdfMake.createPdf(docDefinition);
is this possible to set up an existing blob[pdf] inside document definition (using typescript)?
It seems that no, you can't do that with pdfmake.
Pdfmake is used to create/make a pdf file (in a declarative way), what you seem to want to do is to read one. If you want to add a blob to your document-definition-object I believe you can't unfortunately..
I would suggest you to use something else to read a pdf file from binary data. This may do what you want to achieve.