TypeScript Number toPrecision()

In this chapter, we will explore the toPrecision() method for numbers in TypeScript. This method formats a number to a specified length. Understanding how to use toPrecision() is useful for controlling the number of significant digits in numerical output.

Table of Contents

1. Definition
2. Syntax
3. Examples
4. Conclusion

1. Definition

The toPrecision() method formats a number to a specified length. It returns a string representing the number to the specified precision.

2. Syntax

number.toPrecision(precision);

Parameters

• precision: An integer specifying the number of significant digits. It must be in the range of 1 to 21, inclusive.

Return Value

The method returns a string representing the number formatted to the specified precision.

3. Examples

Let's look at some examples to understand how toPrecision() works in TypeScript.

Example 1: Basic Usage

In this example, we use toPrecision() to format a number to four significant digits.

let num: number = 123.456;
let result = num.toPrecision(4);
console.log(result); // Output: "123.5"

Example 2: Formatting with More Significant Digits

In this example, we use toPrecision() to format a number to six significant digits.

let num: number = 123.456;
let result = num.toPrecision(6);
console.log(result); // Output: "123.456"

Example 3: Using toPrecision() with Small Numbers

In this example, we use toPrecision() to format a small number to three significant digits.

let num: number = 0.00123456;
let result = num.toPrecision(3);
console.log(result); // Output: "0.00123"

Example 4: Using toPrecision() with Large Numbers

In this example, we use toPrecision() to format a large number to five significant digits.

let num: number = 987654321.123;
let result = num.toPrecision(5);
console.log(result); // Output: "9.8765e+8"

Example 5: Using toPrecision() with Integers

In this example, we use toPrecision() to format an integer to three significant digits.

let num: number = 1234;
let result = num.toPrecision(3);
console.log(result); // Output: "1.23e+3"

Example 6: Precision Greater than the Number of Digits

In this example, we use toPrecision() with a precision value greater than the number of digits in the number.

let num: number = 123.45;
let result = num.toPrecision(7);
console.log(result); // Output: "123.4500"

Example 7: Precision of One

In this example, we use toPrecision() with a precision value of one.

let num: number = 123.45;
let result = num.toPrecision(1);
console.log(result); // Output: "1e+2"

4. Conclusion

In this chapter, we explored the toPrecision() method for numbers in TypeScript, which is used to format a number to a specified length. We covered its definition, syntax, parameters, return value, and provided several examples to demonstrate its usage. Understanding how to use toPrecision() effectively can help in various tasks where controlling the number of significant digits in numerical output is required, especially in scientific, financial, and statistical applications.