This is a way to loop through FileReader by using th recursive function that reads the blob file.

LoopingThroughFileReader.js

var foo = new Blob(["Lorem ipsum dolor sit amet, consectetur adipiscing elit."], {
    type: 'text/plain'
});
var bar = new Blob(["Sed tristique ipsum vitae consequat aliquet"], {
    type: 'text/plain'
});

var arrayOfBlobs = [foo, bar];
var arrayIndex = 0;

function fileRead () {
	var me = this;
	if (this.arrayIndex < this.arrayOfBlobs.length) {
		var reader = new FileReader();
	
		function bindedOnload(event) {
			console.log("bindedOnload called");
			console.log("reader results: ", event.target.result);
			this.arrayIndex++;
			this.fileRead();
		}
		
		reader.onload = bindedOnload.bind(me);
		reader.readAsText(this.arrayOfBlobs[arrayIndex]);
	} else {
		console.log("Finished");
	}
}

fileRead();