What exactly do we mean by the term 'object literal' within the realm of TypeScript?

When diving into TypeScript, the term 'object literal' comes up frequently (like in this answer) - but what exactly does 'object literal' mean and how is it different from just an 'object'?

For more insight, you can check out this resource in the official documentation:

Object types

In JavaScript, data is typically grouped and managed using objects. In TypeScript, these are represented as object types.

Literal types

Aside from generic string and number types, specific strings and numbers can be defined in type positions.

While I grasp the concept of literal types when dealing with strings or numbers, where a specific value like "bob" is used instead of the broader string, I'm still curious about object literals.

So, what exactly constitutes an object literal?

typescript

Answer №1

When creating an object literal, curly brackets are used to define the object, like so:

const sample = { greeting: "world" };

This method differs from instantiating a class, such as:

const today = new Date();

(Keep in mind that object literals are not exclusive to TypeScript, they can also be found in plain JavaScript)

Answer №2

Although the TypeScript manual may not cover this topic, it is actually quite straightforward. Essentially, whenever you employ the JavaScript object notation syntax ({ ... }) to establish an object, TypeScript interprets it as an object literal and subjects it to additional type validation.

By using an object literal as a type, TypeScript validates whether the keys in your literal align with those in the target type. This type of validation is often overlooked (for instance, assigning an Orange to a Fruit variable). Object literals are thoroughly scrutinized upon creation. Furthermore, there are some unique interactions that occur when utilizing object literals for generic parameters.

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