A robust JavaScript utility to truncate numbers to a fixed number of decimal places—without rounding errors. Ideal for currency and financial calculations where precision and predictability are critical.
- Truncates numbers to a specified number of decimal places (no rounding)
- Handles both string and number inputs
- Accepts commas or periods as decimal separators
- Supports negative numbers
- Lightweight and dependency-free
- Fully tested with Jest
JavaScript’s native toFixed method rounds values, which can lead to inaccuracies in financial or scientific applications. This package provides a reliable way to truncate (not round) numbers to the desired decimal places, supporting both string and number inputs, and handling commas as decimal separators.
npm install to-fixed-for-realconst toFixed = require('to-fixed-for-real');
console.log(toFixed(12.599, 2)); // 12.59
console.log(toFixed('982,51832', 2)); // 982.51
console.log(toFixed(10, 2)); // 10.0
console.log(toFixed(-21381923.32938989, 2)); // -21381923.32| Input | Code Example | Output |
|---|---|---|
| 12.599, 2 | toFixed(12.599, 2) |
12.59 |
| '982,51832', 2 | toFixed('982,51832', 2) |
982.51 |
| 10, 2 | toFixed(10, 2) |
10.0 |
| -4.3, 2 | toFixed(-4.3, 2) |
-4.3 |
| 1.2345, 2 | toFixed(1.2345, 2) |
1.23 |
| '10.58928', 2 | toFixed('10.58928', 2) |
10.58 |
| '164252,', 2 | toFixed('164252,', 2) |
164252.0 |
| 0, 2 | toFixed(0, 2) |
0 |
// Handles string input with comma as decimal
console.log(toFixed('164252,', 2)); // 164252.0
// Handles string input with no decimals
console.log(toFixed('10', 2)); // 10.0
// Handles zero
console.log(toFixed(0, 2)); // 0| Parameter | Type | Description |
|---|---|---|
num |
number | string | The value to truncate. Accepts numbers or strings (with . or ,). |
floatingPoint |
number | The number of decimal places to keep. If omitted, all decimals are kept. |
Returns: number — The truncated value.
- Truncates, does not round.
- Handles negative numbers and string inputs.
- Converts commas to periods for decimal separation.
This project uses Jest.
npm testContributions, issues, and feature requests are welcome! Please:
- Open an issue for bugs or feature requests
- Fork the repo and submit a pull request for improvements
- Add tests for new features or edge cases
This project is licensed under the MIT License.
nethanos