Sometimes, we may run into the ‘TypeError: X.prototype.y called on incompatible type’ when we’re developing JavaScript apps.
In this article, we’ll look at how to fix the ‘TypeError: X.prototype.y called on incompatible type’ when we’re developing JavaScript apps.
Fix the ‘TypeError: X.prototype.y called on incompatible type’ When Developing JavaScript Apps
To fix the ‘TypeError: X.prototype.y called on incompatible type’ when we’re developing JavaScript apps, we should make sure that we’re calling Function.prototype.call, Function.prototype.apply, or Function.prototype.bind with a this value that is expected.
For instance, if we have:
const mySet = new Set;
['bar', 'baz'].forEach(mySet.add);
then we’ll get the error since the this value in mySet.add isn’t mySet.
To fix this, we write:
const mySet = new Set;
['bar', 'baz'].forEach(mySet.add.bind(mySet));
to call bind with mySet to set mySet as the value of this in the mySet.add method.
Conclusion
To fix the ‘TTypeError: X.prototype.y called on incompatible type’ when we’re developing JavaScript apps, we should make sure that we’re calling Function.prototype.call, Function.prototype.apply, or Function.prototype.bind with a this value that is expected.
