lion/packages/input-amount/src/parsers.js
2019-11-26 18:00:58 +01:00

141 lines
4.8 KiB
JavaScript

import { getDecimalSeparator } from '@lion/localize';
/**
* @param {string} value to evaluate
* @return {boolean} true if value equal . or ,
*/
function isDecimalSeparator(value) {
return value === '.' || value === ',';
}
/**
* Determines the best possible parsing mode.
*
* - If there is only one separator (withLocale)
* - 1,23 => xxx1.23 (heuristic)
* - else parse mode depends mostly on the last 4 chars
* - 1234 => xxx1234 (heuristic)
* - [space]123 => xxx123 (heuristic)
* - ,123 => unclear
* - if 1.000,123 (we find a different separator) => 1000.123 (heuristic)
* - if 1,000,123 (we find only same separators) => 1000123 (unparseable)
* - if 100,123 (we find no more separators) => unclear
* - if en => 100123 (withLocale)
* - if nl => 100.123 (withLocale)
*
* See also {@link parseAmount}
*
* @example
* getParseMode('1.234') => 'withLocale'
*
* @param {string} value Clean number (only [0-9 ,.]) to be parsed
* @return {string} unparseable|withLocale|heuristic
*/
function getParseMode(value, { mode = 'auto' } = {}) {
const separators = value.match(/[., ]/g);
if (mode === 'auto' && separators && separators.length === 1) {
return 'withLocale';
}
if (value.length > 4) {
const charAtLastSeparatorPosition = value[value.length - 4];
if (isDecimalSeparator(charAtLastSeparatorPosition)) {
const firstPart = value.substring(0, value.length - 4);
const otherSeparators = firstPart.match(/[., ]/g);
if (otherSeparators) {
const lastSeparator = charAtLastSeparatorPosition;
return otherSeparators.indexOf(lastSeparator) === -1 ? 'heuristic' : 'unparseable';
}
return 'withLocale';
}
}
return 'heuristic';
}
/**
* Parses numbers by considering the locale.
* Useful for numbers with an ending pair of 3 number chars as in this case you can not be
* certain if it is a group or comma separator. e.g. 1.234; 1,234; 1234.567;
* Taking into consideration the locale we make the best possible assumption.
*
* @example
* parseWithLocale('1.234', { locale: 'en-GB' }) => 1.234
* parseWithLocale('1,234', { locale: 'en-GB' }) => 1234
*
* @param {string} value Number to be parsed
* @param {object} options Locale Options
*/
function parseWithLocale(value, options) {
const locale = options && options.locale ? options.locale : null;
const separator = getDecimalSeparator(locale);
const regexNumberAndLocaleSeparator = new RegExp(`[0-9${separator}-]`, 'g');
let numberAndLocaleSeparator = value.match(regexNumberAndLocaleSeparator).join('');
if (separator === ',') {
numberAndLocaleSeparator = numberAndLocaleSeparator.replace(',', '.');
}
return parseFloat(numberAndLocaleSeparator);
}
/**
* Parses numbers by considering all separators.
* It only keeps the last separator and uses it as decimal separator.
*
* Warning: This function works only with numbers that can be heuristically parsed.
*
* @param {string} value Number that can be heuristically parsed
* @return {float} parsed javascript number
*/
function parseHeuristic(value) {
if (value.match(/[0-9., ]/g)) {
// 1. put placeholder at decimal separator
const numberString = value
.replace(/(,|\.)([^,|.]*)$/g, '_decSep_$2')
.replace(/(,|\.| )/g, '') // 2. remove all thousand separators
.replace(/_decSep_/, '.'); // 3. restore decimal separator
return parseFloat(numberString);
}
return 0;
}
/**
* Parses a number string and returns the best possible javascript number.
* For edge cases it may use locale to give the best possible assumption.
*
* It has 3 "methods" of returning numbers
* - 'unparseable': becomes just numbers
* - 'withLocale': result depends on given or global locale
* - 'heuristic': result depends on considering separators
*
* @example
* parseAmount('1.234.567'); // method: unparseable => 1234567
* parseAmount('1.234'); // method: withLocale => depending on locale 1234 or 1.234
* parseAmount('1.234,56'); // method: heuristic => 1234.56
* parseAmount('1 234.56'); // method: heuristic => 1234.56
* parseAmount('1,234.56'); // method: heuristic => 1234.56
*
* @param {string} value Number to be parsed
* @param {object} options Locale Options
*/
export function parseAmount(value, options) {
const containsNumbers = value.match(/\d/g);
if (!containsNumbers) {
return undefined;
}
const matchedInput = value.match(/[0-9,.\- ]/g);
if (!matchedInput) {
return undefined;
}
const cleanedInput = matchedInput.join('');
const parseMode = getParseMode(cleanedInput, options);
switch (parseMode) {
case 'unparseable':
return parseFloat(cleanedInput.match(/[0-9]/g).join(''));
case 'withLocale':
return parseWithLocale(cleanedInput, options);
case 'heuristic':
return parseHeuristic(cleanedInput);
default:
return 0;
}
}