The Boolean Type in TypeScript

In TypeScript, the boolean type represents one of two values: true or false. These values are commonly used to control program flow, perform comparisons, and express conditions.

Declaring boolean variables in TypeScript is done by specifying the boolean type and assigning a value of true or false.

let isActive: boolean = true;
let isAuthenticated: boolean = false;

Boolean Operators

Comparison Operators

Comparison operators return a boolean value as the result of comparing two values.

• == (equality) and === (strict equality)
• != (inequality) and !== (strict inequality)
• <, <=, >, >=

let x: number = 10;
let y: number = 20;

console.log(x == y);  // false
console.log(x != y);  // true
console.log(x < y);   // true
console.log(x >= y);  // false

Logical Operators

TypeScript supports common logical operators for working with boolean values.

let a: boolean = true;
let b: boolean = false;
console.log(a && b);  // false

console.log(!a);  // false
console.log(!b);  // true

console.log(a || b);  // true

Type Conversion

console.log(Boolean(0));         // false
console.log(Boolean(""));        // false
console.log(Boolean("Hello"));   // true
console.log(Boolean(123));       // true

let trueValue: boolean = true;
let falseValue: boolean = false;

console.log(Number(trueValue));  // 1
console.log(Number(falseValue));  // 0
console.log(String(trueValue));   // "true"
console.log(String(falseValue));   // "false"