How does JavaScript handle floating point precision issues?

JavaScript uses IEEE 754 double-precision (64-bit) floating-point format, which can cause precision issues with decimal numbers.

     console.log(0.1 + 0.2); // 0.30000000000000004
     console.log(0.1 + 0.2 === 0.3); // false
     

Solutions:

1. Using epsilon comparison:

        function areEqual(a, b) {
          return Math.abs(a - b) < Number.EPSILON;
        }
        console.log(areEqual(0.1 + 0.2, 0.3)); // true
        

1. Rounding to fixed decimals:

        const result = Math.round((0.1 + 0.2) * 100) / 100; // 0.3
        

1. Using toFixed() or toPrecision():

        const sum = (0.1 + 0.2).toFixed(2); // "0.30"
        const num = parseFloat(sum); // 0.3
        

1. Working with integers (cents instead of dollars):

        const price1 = 10; // $0.10 as 10 cents
        const price2 = 20; // $0.20 as 20 cents
        const total = price1 + price2; // 30 cents
        const dollars = total / 100; // $0.30
        

1. Using libraries for precise calculations:

        // decimal.js, big.js, or bignumber.js
        const Decimal = require('decimal.js');
        const result = new Decimal(0.1).plus(0.2); // 0.3