# Understanding JavaScript's plus sign in function expressions | Programming

When it comes to JavaScript function expressions, the plus sign can be a bit confusing for beginners. However, its use is actually quite simple and can be a useful tool for concatenating strings and numbers.

## What is a function expression?

A function expression is a way to define a function that is stored as a variable. This allows for the function to be passed around as an argument and used in other functions. Here is an example:

```
const add = function(a, b) {
return a + b;
}
```

In this example, we have defined a function expression called "add" that takes two parameters, "a" and "b", and returns their sum. This function can be called like any other function, such as `add(2, 4)`

which would return `6`

.

## Using the plus sign in function expressions

Now, let's take a look at how the plus sign can be used in function expressions. When used with two operands, the plus sign will add two numbers together. However, when used with a string and a number, it will concatenate them.

Here is an example:

```
const greeting = function(name) {
return "Hello, " + name + "!";
}
```

In this example, we have defined a function expression called "greeting" that takes a parameter called "name" and returns a greeting message that includes the name. The plus sign is used to concatenate the strings "Hello, " and "!" with the variable "name". So, if we call `greeting("John")`

, it will return `"Hello, John!"`

.

The plus sign can also be used to convert a string to a number. For example:

```
const add = function(a, b) {
return +a + +b;
}
```

In this example, we have defined a function expression called "add" that takes two parameters, "a" and "b". The plus sign is used to convert the parameters to numbers before adding them together. So, if we call `add("2", "4")`

, it will return `6`

.

## Conclusion

The plus sign in JavaScript function expressions is a powerful tool for concatenating strings and numbers, as well as converting strings to numbers. Understanding how it works can help you write more efficient and effective code.

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