How to fix variables in javascript

JavaScript is a powerful programming language that is widely used in web development, mobile application and game development. As web applications become more complex, JavaScript programmers often need to process large amounts of data. In situations like this, there are times when fixed-point variables in JavaScript are needed, and that’s what this article is about.

1. What is a fixed-point variable?

In computer programming, floating-point numbers and fixed-point numbers are common numerical representations. Floating point is a data type with uncertain precision. Its value can be very small or very large. For some calculations that require high precision, errors often occur. Fixed-point numbers are a fixed-precision numerical representation that can maintain accuracy during storage and operation without loss of precision.

In JavaScript, since the default numerical type is floating point, some special methods are needed to implement fixed-point operations. JavaScript can implement fixed-point numbers by manually specifying the precision, or by using some ready-made libraries, such as Big.js and Decimal.js.

2. Manually specify the precision

Manually specifying the precision is a relatively simple way to implement fixed-point numbers. It requires manually specifying the precision, and then converting it during operation. Finally, Then convert the result back.

For example, if we want to calculate the sum of two decimals with a precision of 2 digits, we can do it as follows:

var a = 3.1415;
var b = 2.7182;
var p = 100; // p表示精度
var c = Math.round((a + b) * p) / p; // 四舍五入保留p位小数

In the above code, we set the precision to 100, that is Keep 2 decimal places. Then use the Math.round function to perform the rounding operation, and finally divide the result by the precision to get the calculation result with 2 decimal places.

This method is relatively simple, but it requires manually setting the precision and performing conversion operations during each operation, so it is relatively inefficient for a large number of computing tasks.

3. Using Big.js library

Big.js is an open source JavaScript library that provides high-precision decimal numerical operations. The library supports basic operations such as addition, subtraction, multiplication, division and exponentiation. It also supports operations such as rounding, rounding and comparison, which can meet most computing tasks that require high precision.

It is very simple to use the Big.js library to calculate fixed-point numbers. Just pass the number that requires precision control into the Big.js function:

var Big = require('big.js');
var a = new Big('3.1415');
var b = new Big('2.7182');
var c = a.plus(b);
console.log(c.toFixed(2)); // 5.86

4. Use Decimal.js Library

Decimal.js is another JavaScript high-precision mathematics library. Similar to Big.js, it provides basic mathematical operations and supports high-precision calculations.

Using Decimal.js to calculate fixed-point numbers is also very simple:

var Decimal = require('decimal.js');
var a = new Decimal('3.1415');
var b = new Decimal('2.7182');
var c = a.plus(b);
console.log(c.toDecimalPlaces(2).toString()); // 5.86

5. Summary

This article introduces the method of implementing fixed-point numbers in JavaScript. Including manually specifying precision, using the Big.js library and using the Decimal.js library, etc. In actual development, we can choose different implementation methods according to actual needs to meet our own computing needs.

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