After Effects Expressions: Get Current Key

In After Effects, expressions are a powerful tool for automating tasks and creating complex animations. However, when working with functions as expression parameters, it's essential to understand how they are evaluated at design time. In this article, we'll explore the best practices for using functions in expressions and provide examples of how to get current key values.

Design Time Evaluation

When designing an expression, it's crucial to ensure that all functions can be fully evaluated at design time. This means that any function parameters should be evaluated from left to right, without relying on runtime evaluation.

For instance, consider the following example:

```

customerName = 'SophiaOwen': 'lastName': parameters('firstName')

```

In this case, the `parameters()` function is used to evaluate the `firstName` parameter and assign the result to the `customerName` property. This approach ensures that the expression can be evaluated at design time.

Using Functions in Expressions

Functions can be used in expressions to perform various tasks, such as combining strings or calculating values using math functions. For example:

```

accountName = concat('account-', parameters('customerName'))

```

In this example, the `concat()` function is used to combine two string values: `'account-'` and the value of the `customerName` parameter.

Nested Functions

Expressions can also include nested functions, which allow you to perform complex operations. For instance:

```

function getAccountName() {

return concat('account-', parameters('customerName'))

}

accountName = getAccountName()

```

In this example, the `getAccountName()` function is defined as a nested expression that returns the combined string value of `'account-'` and the `customerName` parameter.

When working with expressions in After Effects, it's essential to understand how functions are evaluated at design time. By using functions correctly, you can create complex animations and automate tasks with ease.

In conclusion, this article has provided an overview of the best practices for using functions in expressions in After Effects. Whether you're new to expressions or a seasoned pro, understanding how to use functions effectively will help you achieve your creative goals.

After effects expressions get current key