Type conversion in JavaScript refers to the process of converting a value from one data type to another. JavaScript is a dynamically-typed language, which means that the type of a variable can change during runtime. As a result, it's often necessary to perform type conversions in order to ensure that your code is functioning as intended.

There are two main ways to perform type conversions in JavaScript: explicit and implicit conversions.

Explicit conversions occur when you use one of the type conversion functions provided by JavaScript, such as String(), Number(), Boolean(), **toString()** and parseInt(). Here are some examples:

let x = 123;
let y = String(x); // y is now a string "123"
 
let a = '4.56';
let b = Number(a); // b is now a number 4.56
 
let c = 'true';
let d = Boolean(c); // d is now a boolean value true

Implicit conversions occur automatically when you perform certain operations, such as addition or comparison, between values of different types. For example:

let x = '123';
let y = 456;
let z = x + y; // z is now the string "123456"
 
let a = 'hello';
let b = 123;
let c = a < b; // c is now false

It's important to be mindful of type conversions in JavaScript, as they can sometimes lead to unexpected results. For example, if you're performing arithmetic operations with numbers, it's a good idea to make sure that the values you're working with are actually numbers, rather than strings that happen to look like numbers.