Accessing an Image SRC from code

Question

I'm working on a Sitecore JSS site, Angular framework, disconnected mode.

I'm trying to access the SRC attribute of an image field in my components ngOnInit method. Stepping through the code, it looks like what I've got is right, but the compiler says that "value" does not exist. The line in question looks like:

this.heroImage = this.rendering.fields.heroImage.value.src;

How do I correctly retrieve the SRC attribute of the image?

Note: this.heroImage is a string.