To fix cannot read properties of undefined (reading ‘push’) error with JavaScript, we should make sure we’re calling push on an array.
For instance, we write
const arr = [1, 2, 3, 4];
arr.push(5);
to call push on arr with 5 to append 5 as the last item of the arr array.
We can check if a variable is an array with the Array.isArray method.
