Principle of data types and their conversion

Use of data types

Principle of data types and their conversion

Data type is a kind or form of value store in a declare variable. Is the value store a number or string?

Types of data type:

a. Primitive data types

b. Non primitives data types

Primitive Data-types

  1. Number

  2. String

  3. Boolean

  4. Undefined

  5. Null

  6. BigInt

  7. Symbol

Non-Primitive Data-types

  1. Object

  2. Array

  3. RegExp

JavaScript has some in built conversion one can explore without the use of methods:

let result;
//For example =>
// String conversion
result = '3' + 2;  // "32"
result = '10' + true;  //"10true"

//Number conversion
result = '10' - '2'; // 8 
result = '10' - 2; //8

//NaN conversion
result = 'hello' - 'world'; // NaN 
result = '4' - 'hello'; //NaN

//Boolean conversion
result = '8' - true;  // 7 
result = 4 + true; //5

//Null conversion
result = 15 + null;  // 15
result = 4 - null; //4

To determine types of data type use, the keyword typeof helps check.

console.log(typeof(num)); //Number

Modification of data types (converting)

Changing a value stored from one data types to another

Changing value of the declare variable to a different data types can be done by ensuring that the data type being converted to, is the one use and begins with a Capital letter. Clear example:

let year = String(1980); 
console.log(year);  //"1980"

methods

This value was a number data type and then converted to a string data type using String

Generally:

let x = Data-types(value);

convert to number

A string value change to number type by using Number keyword, as well as some data types such as boolean and null in JavaScript.

For example: true is known as 1 while false, empty string "" and null is 0 or empty value.

A text, NaN and undefined will return Not a Number NaN

Number Conversion

Some method use in Number type

some specific method can be used to convert one data types to a number. Method like:

1. parseInt()
2. parseFloat()
3. /*unary operator*/ +"" 
4. Math.floor()

example:

Number Conversion using methods

convert to string

conversion to string is done with String /*or*/ toString(). example:

String Conversion

convert to boolean

empty string, 0, undefined, NaN and null return false when passed with boolean but others return true. example:

Boolean Conversion

Double Not !!can be use as boolean converter

console.log(!!1); //true
console.log(!!0); //false
console.log(!!null); //false

More article on each of this data types both primitive and non-primitive types coming soon...

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