andreaspitzer/parse-decimal-number

Parse a decimal number with i18n format support (localized decimal points and thousands separators)

OK, let’s fix international numbers parsing and validation once and forever. I got the inspiration for this in a UI project because somehow the libraries we used didn’t do a great job, so I wrote my own parser, and this is a more polished version of it.

These are the design goals:

• Simple. String in, float out, done. ✓
• Accurate. Parses numbers and returns NaN for non-numbers. (=good for input validation) ✓
• Lightweight. (<1k minified) ✓
• Complete. No external dependencies ✓
• Solid. 100% Code Coverage ✓
• CLDR Support. Supports cldr data ✓

In it’s simplest form, you just use it as a parseFloat replacement.

npm i parse-decimal-number --save

parseDecimalNumber = require('parse-decimal-number');
console.log(parseDecimalNumber('12,345,678.90'));
// -> 12345678.90

console.log(parseDecimalNumber('12.345.678,90','.,'));
// -> 12345678.90

Returns a float representation of string or NaN if string is not a parseable number. Use the optional options parameter to specify the thousands and decimal point characters.

string A String that is supposed to contain a number.

options optional A string, array or hash with thousands and decimal separators.

• String a two-character string consisting of the thousands character followed by the decimal point character, e.g. ',.'

• Array An array of two elements, the first being the thousands character, the second being the decimal point character, e.g. ['.',',']

• Hash with the following elements (this is compatible with NumeralJS)

  • thousands thousands separator character. Default: ,
  • decimal decimal point character. Default: .

enforceGroupSize A boolean indicating whether to support that individual groups between the thousands character are exactly 3 digits

console.log(parseDecimalNumber('12.345.678,90'));
// -> 12345678.90

console.log(parseDecimalNumber('12.345.678,90','.,'));
// -> 12345678.90

console.log(parseDecimalNumber('12.345.678,90',['.',',']));
// -> 12345678.90

var customSeparators = {thousands:'.',decimal:','};
console.log(parseDecimalNumber('12.345.678,90',customSeparators));
// -> 12345678.90

Returns a function that will take a string as an argument and return a float or NaN, just like parseDecimalNumber.

  const cldr = require('cldr');

  const locale = 'de_DE';
  const options = cldr.extractNumberSymbols(locale);

  const parse = parseDecimalNumber.withOptions(options);

  parse('123.456.789,0123'); // -> 123456789.0123

Set the default thousands and decimal characters that are used when no options are passed to parseDecimalNumber.

var defaultSeparators = {thousands:'.',decimal:','};
parseDecimalNumber.setOptions(defaultSeparators);

console.log(parseDecimalNumber('12.345.678,90'));
// -> 12345678.90

has the same effect as parseDecimalNumber.setOptions({thousands:',',decimal:'.'};)

You can easily apply CLDR data using the cldr package:

  const cldr = require('cldr');

  parseDecimalNumber(
    '12.345.678,90',
    cldr.extractNumberSymbols('de_DE')
  );

Numeral.js is good at formatting numbers and comes with an extensive set of locale data that you can use with parse-decimal-number.

If you use numeral in your project, you can use their locale data as follows:

parseDecimalNumber('12.345.678,90', numeral.localeData('de').delimiters);
// -> 12345678.9

You can of course use the same data to set the default values for parse-decimal-number:

parseDecimalNumber.setOptions(numeral.localeData('de').delimiters);
parseDecimalNumber('12.345.678,90');
// -> 12345678.9

Done☺️

To keep this project as small and modular as possible, the locale data itself has been left out of this library. If you need locale date, other projects might be helpful:

• cldr
• Numeral
• jsi18n
• Unicode Common Locale Data Repository
• Wikipedia

{%= include("tests") %}

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality, and please re-build the documentation with gulp-verb before submitting a pull request.

Andreas Pizsa (http://.com/AndreasPizsa)

• /AndreasPizsa
• twitter/AndreasPizsa

Copyright (c) 2017 Andreas Pizsa (http://.com/AndreasPizsa), contributors.