gristlabs_grist-core/app/common/NumberFormat.ts

80 lines
3.3 KiB
TypeScript
Raw Normal View History

/**
* Here are the most relevant formats we want to support.
* -1234.56 Plain
* -1,234.56 Number (with separators)
* 12.34% Percent
* 1.23E3 Scientific
* $(1,234.56) Accounting
* (1,234.56) Financial
* -$1,234.56 Currency
*
* We implement a button-based UI, using one selector button to choose mode:
* none = NumMode undefined (plain number, no thousand separators)
* `$` = NumMode 'currency'
* `,` = NumMode 'decimal' (plain number, with thousand separators)
* `%` = NumMode 'percent'
* `Exp` = NumMode 'scientific'
* A second toggle button is `(-)` for Sign, to use parentheses rather than "-" for negative
* numbers. It is Ignored and disabled when mode is 'scientific'.
*/
import {clamp} from 'app/common/gutil';
import * as LocaleCurrency from "locale-currency";
import {FormatOptions} from 'app/common/ValueFormatter';
import {DocumentSettings} from 'app/common/DocumentSettings';
// Options for number formatting.
export type NumMode = 'currency' | 'decimal' | 'percent' | 'scientific';
export type NumSign = 'parens';
export interface NumberFormatOptions extends FormatOptions {
numMode?: NumMode;
numSign?: NumSign;
decimals?: number; // aka minimum fraction digits
maxDecimals?: number;
currency?: string;
}
export function getCurrency(options: NumberFormatOptions, docSettings: DocumentSettings): string {
return options.currency || docSettings.currency || LocaleCurrency.getCurrency(docSettings.locale);
}
export function buildNumberFormat(options: NumberFormatOptions, docSettings: DocumentSettings): Intl.NumberFormat {
const currency = getCurrency(options, docSettings);
const nfOptions: Intl.NumberFormatOptions = parseNumMode(options.numMode, currency);
// numSign is implemented outside of Intl.NumberFormat since the latter's similar 'currencySign'
// option is not well-supported, and doesn't apply to non-currency formats.
if (options.decimals !== undefined) {
// Should be at least 0
nfOptions.minimumFractionDigits = clamp(Number(options.decimals), 0, 20);
}
// maximumFractionDigits must not be less than the minimum, so we need to know the minimum
// implied by numMode.
const tmp = new Intl.NumberFormat(docSettings.locale, nfOptions).resolvedOptions();
if (options.maxDecimals !== undefined) {
// Should be at least 0 and at least minimumFractionDigits.
nfOptions.maximumFractionDigits = clamp(Number(options.maxDecimals), tmp.minimumFractionDigits || 0, 20);
} else if (!options.numMode) {
// For the default format, keep max digits at 10 as we had before.
nfOptions.maximumFractionDigits = clamp(10, tmp.minimumFractionDigits || 0, 20);
}
return new Intl.NumberFormat(docSettings.locale, nfOptions);
}
export function parseNumMode(numMode?: NumMode, currency?: string): Intl.NumberFormatOptions {
switch (numMode) {
case 'currency': return {style: 'currency', currency, currencyDisplay: 'narrowSymbol' };
case 'decimal': return {useGrouping: true};
case 'percent': return {style: 'percent'};
// TODO 'notation' option (and therefore numMode 'scientific') works on recent Firefox and
// Chrome, not on Safari or Node 10.
case 'scientific': return {notation: 'scientific'} as Intl.NumberFormatOptions;
default: return {useGrouping: false};
}
}