CODEWITHSUNDEEP
javascriptangulartypescriptfilereadertypescript2.0
Prajwal
Prajwal

Reputation: 4000

Angular2 - Access component properties from method of properties

I'm trying to read a file and store the read content in a private variable of Component. So far, I cannot access properties of components, as I get referral for this as FileReader not component.

My code is like this

private ReadTheFile(file:File) {

    var myReader: FileReader = new FileReader();
    myReader.readAsText(file);
    myReader.onloadend = function (e) {

        //Do something here with myReader.result

    }

    //Get the modified result here, and assign it to public property.

}

So, how to access Component properties inside a method like this? Which is method of FileReader instance, not Component.

Upvotes: 1

Views: 796

Answers (2)

Poul Kruijt
Poul Kruijt

Reputation: 71911

Don't use the keyword function inside a class. This will change the this context as you've noticed. use the arrow function

private ReadTheFile(file:File) {

    var myReader: FileReader = new FileReader();
    myReader.readAsText(file);
    myReader.onloadend = (e) => {

        //Do something here with myReader.result

    }

    //Get the modified result here, and assign it to public property.

}

Upvotes: 4

Bartek Fryzowicz
Bartek Fryzowicz

Reputation: 6674

You can use an arrow function to preserve component context:

myReader.onloadend = (e) => {
        //Do something here with myReader.result

    }

Upvotes: 1

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