TypeScript Simple Types
TypeScript supports some simple types (primitives) you may know.
There are three main primitives in JavaScript and TypeScript.
boolean- true or false valuesnumber- whole numbers and floating point valuesstring- text values like "TypeScript Rocks"
Type Assignment
When creating a variable, there are two main ways TypeScript assigns a type:
- Explicit
- Implicit
In both examples below firstName is of type string
Explict Type
Explicit - writing out the type:
let firstName: string = "Dylan";
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Explicit type assignment are easier to read and more intentional.
Implicit Type
Implicit - TypeScript will "guess" the type, based on the assigned value:
let firstName = "Dylan";
Try it Yourself »
Note: Having TypeScript "guess" the type of a value is called infer.
Implicit assignment forces TypeScript to infer the value.
Implicit type assignment are shorter, faster to type, and often used when developing and testing.