By applying the if condition below, I can determine whether or not the local storage key exists:
this.data = localStorage.getItem('education');
if(this.data) {
console.log("Exists");
}
To check for its non-existence using an if condition without resorting to 'else', how would I code that?
When checking if the this.data is undefined, using !(this.data) seems like a valid approach:
if (!(this.data)) { console.log("DOH!"); }
However, it's important to consider all possibilities. What if the key is actually set to false? Just relying on !(this.data) won't cover that case. It might be better to use the in keyword as suggested in this answer.
if (!("data" in this)) { console.log("DOH!"); }
For example:
obj = { a: false, b: undefined }
if (!("a" in obj)) { console.log("a does not exist"); }
if (!("b" in obj)) { console.log("b does not exist"); }
if (!("c" in obj)) { console.log("c does not exist"); }
The output would be:
c does not exist
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