In this example, I have the basic structure of my code:
let myArray: (Array<any> | null);
if (cnd) {
myArray = [];
myArray?.push(elt); // Curious about this line
myArray[0].key = value; // Questioning this line
} else {
myArray = null;
}
Why is the ? symbol necessary in the line where myArray has already been assigned to an empty array?
Is there a specific syntax to prevent the error message "Object is possibly null" when accessing the key property?
Thank you for your assistance.
In my opinion, humans still hold the edge over typecheckers in terms of problem-solving abilities. Although it may seem unsatisfying, the truth remains that humans possess a deeper understanding and intuition when it comes to complex situations like this one. Typecheckers, on the other hand, often rely on simple conditional statements to make decisions on null values. While the code example provided here may appear somewhat artificial, I believe that restructuring it as follows could provide more clarity:
var myArray: (Array<any> | null);
if (condition) {
element.key = value;
myArray = [element];
} else {
myArray = null;
}
By making these adjustments, we can eliminate those peculiarities.
When tackling question 1, make sure to check out this resource
Regarding question 2, it's important to perform a null check like the following before accessing your object
if (obj !== null) {
obj.doSomeThing();
}
Alternatively, you can simply do the following if your object may be null or undefined. Null and undefined are considered falsy values, so they are automatically coerced to false in boolean contexts
if (obj) {
obj.doSomeThing();
}
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