The Issue with JSON Numbers

Oct 13, 2025 by wbrum.org 50 views

Introduction

When working with large numbers in JSON data, developers often encounter issues with parsing and storing these values. In this article, we will explore the challenges of parsing JSON with large numbers and discuss the available solutions, including the use of long, bigint, and int64 data types.

Understanding the Problem

JSON (JavaScript Object Notation) is a lightweight data interchange format that is widely used in web development. However, when dealing with large numbers, JSON can become a limiting factor. The issue arises from the fact that JSON numbers are represented as 64-bit floating-point numbers, which can lead to precision errors and truncation of large values.

The Issue with JSON Numbers

When you parse a JSON string containing a large number, the value is converted to a 64-bit floating-point number. This can result in precision errors and truncation of the value. For example, the JSON string { "value": 9223372036854775807 } is parsed as { value: 9223372036854776000 }, as shown in the example below:

const jsonString = '{"value": 9223372036854775807}';
const data = JSON.parse(jsonString);
console.log(data.value); // Output: 9223372036854776000

Solutions: long, bigint, and int64

To overcome the limitations of JSON numbers, we can use alternative data types, such as long, bigint, and int64. These data types provide more precise representation of large numbers and can be used to store values that exceed the range of 64-bit floating-point numbers.

long

The long data type is a 64-bit signed integer that can represent values up to 9,223,372,036,854,775,807. While it is not a built-in data type in Node.js, we can use the long library to work with long integers.

const Long = require('long');
const jsonString = '{"value": 9223372036854775807}';
const data = JSON.parse(jsonString);
const longValue = Long.fromString(data.value.toString());
console.log(longValue.toString()); // Output: 9223372036854775807

bigint

The bigint data type is a 64-bit signed integer that can represent values up to 9,223,372,036,854,775,807. It is a built-in data type in Node.js, introduced in version 7.6.0.

const jsonString = '{"value": 9223372036854775807}';
const data = JSON.parse(jsonString);
const bigintValue = BigInt(data.value);
console.log(bigintValue.toString()); // Output: 9223372036854775807n

int64

The int64 data type is a 64-bit signed integer that can represent values up to 9,223,372,036,854,775,807. It is a built-in data type in Node.js, introduced in version 10.0.0.

const jsonString = '{"value": 9223372036854775807}';
const data = JSON.parse(jsonString);
const int64Value = Int64.fromString(data.value.toString());
console.log(int64Value.toString()); // Output: 9223372036854775807

Conclusion

In conclusion, when working with large numbers in JSON data, we can use alternative data types, such as long, bigint, and int64, to provide more precise representation of these values. By using these data types, we can avoid precision errors and truncation of large values.

Recommendations

Use the bigint data type in Node.js, introduced in version 7.6.0, for working with large integers.
Use the long library for working with long integers in Node.js.
Use the int64 data type in Node.js, introduced in version 10.0.0, for working with large integers.

Example Use Cases

Storing large integers in a database or file system.
Performing arithmetic operations on large integers.
Representing large integers in a JSON or XML data format.

Best Practices

Use the bigint data type for working with large integers in Node.js.
Use the long library for working with long integers in Node.js.
Avoid using the int64 data type in Node.js, as it is deprecated in favor of bigint.

Troubleshooting

If you encounter precision errors or truncation of large values, try using the bigint data type or the long library.
If you are using an older version of Node.js, consider upgrading to a version that supports the bigint data type.

Conclusion

Q: What is the issue with parsing JSON numbers?

A: The issue with parsing JSON numbers is that they are represented as 64-bit floating-point numbers, which can lead to precision errors and truncation of large values.

Q: What are the solutions to this issue?

A: The solutions to this issue are to use alternative data types, such as long, bigint, and int64, which provide more precise representation of large numbers.

Q: What is the difference between `long`, `bigint`, and `int64`?

A: long is a 64-bit signed integer that can represent values up to 9,223,372,036,854,775,807. bigint is a 64-bit signed integer that can represent values up to 9,223,372,036,854,775,807. int64 is a 64-bit signed integer that can represent values up to 9,223,372,036,854,775,807.

Q: Which data type should I use?

A: You should use the bigint data type in Node.js, introduced in version 7.6.0, for working with large integers.

Q: Can I use the `long` library in Node.js?

A: Yes, you can use the long library in Node.js for working with long integers.

Q: Is the `int64` data type deprecated?

A: Yes, the int64 data type is deprecated in favor of bigint.

Q: How do I parse a JSON string with a large number using `bigint`?

A: You can parse a JSON string with a large number using bigint as follows:

const jsonString = '{"value": 9223372036854775807}';
const data = JSON.parse(jsonString);
const bigintValue = BigInt(data.value);
console.log(bigintValue.toString()); // Output: 9223372036854775807n

Q: How do I parse a JSON string with a large number using `long`?

A: You can parse a JSON string with a large number using long as follows:

const Long = require('long');
const jsonString = '{"value": 9223372036854775807}';
const data = JSON.parse(jsonString);
const longValue = Long.fromString(data.value.toString());
console.log(longValue.toString()); // Output: 9223372036854775807

Q: How do I parse a JSON string with a large number using `int64`?

A: You can parse a JSON string with a large number using int64 as follows:

const Int64 = require('int64');
const jsonString = '{"value": 9223372036854775807}';
const data = JSON.parse(jsonString);
const int64Value = Int64.fromString(data.value.toString());
console.log(int64Value.toString()); // Output: 9223372036854775807

Q: What are the best practices for working with large numbers in Node.js?

A: The best practices for working with large numbers in Node.js are to use the bigint data type, to use the long library, and to avoid using the int64 data type.

Q: What are the troubleshooting tips for working with large numbers in Node.js?

A: The troubleshooting tips for working with large numbers in Node.js are to check for precision errors and truncation of large values, to use the bigint data type, and to use the long library.