Can you explain the significance of foo === +bar?

Currently, I am diving into the world of express and came across a coding challenge that involves downloading a zip file and performing certain tasks. While going through the code, there is a specific line that is causing confusion:

const recipe = recipes.find( ({ id }) => {
return id === +recipeId; }
);

The question that arises is, what exactly does the +recipeId accomplish in this context?

For clarity, recipeId is an integer value, such as 2 or 3. Could someone explain the purpose of the plus sign preceding it in the given expression? Additionally, it's worth noting that recipes is an object containing various recipe entries.

Answer №1

Utilizing the + operator in this context ensures that the id is strictly compared with a number, specifically recipeId. This precaution is taken to ensure that even if recipeId is a string such as "2", it is first converted to a number using the unary operator + before being compared with id.

For instance, consider a scenario where id=2 and recipeId="2".

Then id === recipeId would result in false since the === operator also verifies the data types of the operands.

In order for it to evaluate as true, both operands must be of the same type and contain matching values. Thus, by employing +recipeId, we successfully convert recipeId to a number, resulting in a final output of true.

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