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Showing content from https://www.typescripttutorial.net/typescript-tutorial/typescript-boolean/ below:

TypeScript Boolean

Summary: in this tutorial, you will learn about the TypeScript boolean data type and how to use the boolean keyword.

Introduction to the TypeScript boolean

The TypeScript boolean type has two values: true and false. The boolean type is one of the primitive types in TypeScript.

Declaring boolean variables

In TypeScript, you can declare a boolean variable using the boolean keyword. For example:

let pending: boolean;
pending = true;


pending = false;Code language: JavaScript (javascript)
Boolean operator

To manipulate boolean values, you use the boolean operators. TypeScript supports common boolean operators:

Operator Meaning && Logical AND operator || Logical OR operator ! Logical NOT operator

For example:


const pending: boolean = true;
const notPending = !pending; 
console.log(result); 

const hasError: boolean = false;
const completed: boolean = true;


let result = completed && hasError; 
console.log(result); 


result = completed || hasError; 
console.log(result); Code language: JavaScript (javascript)
Type annotations for boolean

As seen in previous examples, you can use the boolean keyword to annotate the types for the boolean variables:

let completed: boolean = true;Code language: JavaScript (javascript)

However, TypeScript often infers types automatically, so type annotations may not be necessary:

let completed = true;Code language: JavaScript (javascript)

Like a variable, you can annotate boolean parameters or return the type of a function using the boolean keyword:

function changeStatus(status: boolean): boolean {
   
}Code language: JavaScript (javascript)
Boolean Type

JavaScript has the Boolean type that refers to the non-primitive boxed object. The Boolean type has the letter B in uppercase, which is different from the boolean type.

It’s a good practice to avoid using the Boolean type.

Summary

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