Understanding JavaScript Conversion Functions

Understanding JavaScript Conversion Functions

JavaScript provides a variety of functions to convert data from one type to another. These conversion functions are essential for handling and manipulating data effectively. In this article, we will explore some common JavaScript functions like parseInt() and their counterparts, explaining their usage with clear examples to help them understand.

1. parseInt()

Description

The parseInt() function converts a string into an integer.

Syntax

parseInt(string, radix);
  • string: The string to be parsed.

  • radix: The base of the number system (2 to 36). Defaults to 10 if not provided.

Examples

parseInt("42");        // Returns 42
parseInt("101", 2);    // Returns 5 (binary to decimal)
parseInt("7F", 16);    // Returns 127 (hexadecimal to decimal)

2. parseFloat()

Description

The parseFloat() function converts a string into a floating-point number.

Syntax

parseFloat(string);
  • string: The string to be parsed.

Examples

parseFloat("3.14");    // Returns 3.14
parseFloat("123abc");  // Returns 123

3. Number()

Description

The Number() function converts a value to a number.

Syntax

Number(value);
  • value: The value to be converted.

Examples

Number("123");    // Returns 123
Number("123.45"); // Returns 123.45
Number("abc");    // Returns NaN

4. String()

Description

The String() function converts a value to a string.

Syntax

String(value);
  • value: The value to be converted.

Examples

String(123);    // Returns "123"
String(true);   // Returns "true"

5. toString()

Description

The toString() method converts a number to a string.

Syntax

number.toString([radix]);
  • radix: Optional. Specifies the base of the number system (2 to 36).

Examples

(123).toString();    // Returns "123"
(123).toString(2);   // Returns "1111011" (binary)

6. Boolean()

Description

The Boolean() function converts a value to a boolean.

Syntax

Boolean(value);
  • value: The value to be converted.

Examples

Boolean(1);      // Returns true
Boolean(0);      // Returns false
Boolean("");     // Returns false

7. Date.parse()

Description

The Date.parse() function parses a string representation of a date and returns the number of milliseconds since January 1, 1970.

Syntax

Date.parse(dateString);
  • dateString: The string to be parsed.

Examples

Date.parse("2024-07-14T00:00:00Z"); // Returns 1720569600000

8. JSON.parse()

Description

The JSON.parse() function parses a JSON string and returns the corresponding JavaScript object.

Syntax

JSON.parse(text);
  • text: The JSON string to be parsed.

Examples

let jsonString = '{"name":"John", "age":30}';
let obj = JSON.parse(jsonString);  // Returns {name: "John", age: 30}

9. JSON.stringify()

Description

The JSON.stringify() function converts a JavaScript object or value to a JSON string.

Syntax

JSON.stringify(value, [replacer], [space]);
  • value: The value to be converted.

  • replacer: Optional. A function or array that transforms the results.

  • space: Optional. A string or number that's used to insert white space into the output JSON string for readability purposes.

Examples

let obj = {name: "John", age: 30};
let jsonString = JSON.stringify(obj); // Returns '{"name":"John","age":30}'

10. Intl.NumberFormat()

Description

The Intl.NumberFormat object is a constructor for objects that enable language-sensitive number formatting.

Syntax

new Intl.NumberFormat([locales], [options]).format(number);
  • locales: Optional. A string with a BCP 47 language tag, or an array of such strings.

  • options: Optional. An object with configuration properties.

Examples

let number = 123456.789;
let formattedNumber = new Intl.NumberFormat('en-US').format(number); // Returns "123,456.789"

11. Math.round(), Math.floor(), Math.ceil()

Description

These functions round numbers to the nearest integer, down to the nearest integer, or up to the nearest integer, respectively.

Syntax

Math.round(number);  // Rounds to the nearest integer
Math.floor(number);  // Rounds down to the nearest integer
Math.ceil(number);   // Rounds up to the nearest integer

Examples

Math.round(4.5);   // Returns 5
Math.floor(4.9);   // Returns 4
Math.ceil(4.1);    // Returns 5

Conclusion

Understanding these JavaScript conversion functions is crucial for effectively working with different data types. Whether you need to convert strings to numbers, format numbers, or handle JSON data, these functions provide the necessary tools to manipulate and utilize data in your applications. With clear examples, beginners can easily grasp how to use these functions and apply them in their coding projects.