Follow

Keep Up to Date with the Most Important News

By pressing the Subscribe button, you confirm that you have read and are agreeing to our Privacy Policy and Terms of Use
Contact

Unable to define this context in document.eventListener

I am implementing a scenario in which on clicking outside the drawer, i want to execute the saveChange action but somehow it is giving me the error that saveChange is not a function. I tried different ways to set the context but it is not working.

export default class DrawerModel {
    constructor(context) {
        this.data = context.primaryInfoData;
        this.name = ko.observable('test');
    
        document.addEventListener("click", function (e) {
            var self= this;
            var element = e.target;
            let isOutside = true;
            for (var element = e.target; element; element = element.parentNode) {
                if (element.id === 'drawer_primaryInfoDrawer') {
                   isOutside = false;
                }
            }
            if(isOutside) {
                    self.saveChanges();
            }           
            
        });
    }

    saveChanges() {
       const data = {
        title: this.name(),
       }
        this.data.valueChangeHandler(data);
    };

}

Error :

Uncaught TypeError: self.saveChanges is not a function

MEDevel.com: Open-source for Healthcare and Education

Collecting and validating open-source software for healthcare, education, enterprise, development, medical imaging, medical records, and digital pathology.

Visit Medevel

>Solution :

this is because in your event listener, this refers to the window instead of your class. you can fix this by adding .bind(this) to your function like so:

document.addEventListener("click", function (e) {
    // ...
}.bind(this));
Add a comment

Leave a Reply

Keep Up to Date with the Most Important News

By pressing the Subscribe button, you confirm that you have read and are agreeing to our Privacy Policy and Terms of Use

Discover more from Dev solutions

Subscribe now to keep reading and get access to the full archive.

Continue reading