compact missing from Int.NumberFormat.formatToParts

[mjpieters]

TypeScript Version: 4.2.0-dev.20201221

Search Terms: NumberFormat.formatToParts, compact

Expected behavior:

part: 'compact' is a valid part type, as per EMCA 402, section 12.1.7 (PartitionNotationSubPattern), step 4. - c. - iv. - 2.:

iv. Else if p is equal to "compactSymbol", then

1. [...]
2. Append a new Record { [[Type]]: "compact", [[Value]]: compactSymbol } as the last element of result.

Note that the MDN documentation for Intl.NumberFormat.prototype.formatToParts() doesn't mention this part type either; see mdn/content#516.

Actual behavior:

The Intl.NumberFormatPartTypes type should include "compact".

Related Issues:

• Intl.formatByParts() doesn't support the "unit" part type #42004 (Intl.formatByParts() doesn't support the "unit" part type, different part type, same area).

Code

const compactFormat = Intl.NumberFormat('en', {
 notation: 'compact',
 compactDisplay: 'short',
 style: 'decimal',
 maximumFractionDigits: 3,
})

// formatValue(42174812) => {formatted: '42.175', magnitude: 'M'}
function formatValue(value: number): {formatted: string, magnitude: string} {
 let magnitude = ''
 return {
 formatted: compactFormat
 .formatToParts(value)
 .reduce((formatted, part) => {
 switch (part.type) {
 case 'compact':
 magnitude = magnitude + part.value
 break
 default:
 formatted = formatted + part.value
 }
 return formatted
 }, ''),
 magnitude: magnitude
 }
}

console.log(formatValue(42174812))

Output

"use strict";
const compactFormat = Intl.NumberFormat('en', {
 notation: 'compact',
 compactDisplay: 'short',
 style: 'decimal',
 maximumFractionDigits: 3,
});
// formatValue(42174812) => {formatted: '42.175', magnitude: 'M'}
function formatValue(value) {
 let magnitude = '';
 return {
 formatted: compactFormat
 .formatToParts(value)
 .reduce((formatted, part) => {
 switch (part.type) {
 case 'compact':
 magnitude = magnitude + part.value;
 break;
 default:
 formatted = formatted + part.value;
 }
 return formatted;
 }, ''),
 magnitude: magnitude
 };
}
console.log(formatValue(42174812));

Compiler Options

{
 "compilerOptions": {
 "noImplicitAny": true,
 "strictNullChecks": true,
 "strictFunctionTypes": true,
 "strictPropertyInitialization": true,
 "strictBindCallApply": true,
 "noImplicitThis": true,
 "noImplicitReturns": true,
 "alwaysStrict": true,
 "esModuleInterop": true,
 "declaration": true,
 "experimentalDecorators": true,
 "emitDecoratorMetadata": true,
 "moduleResolution": 2,
 "target": "Latest",
 "module": "ESNext"
 }
}

Playground Link: Provided

[MartinJohns]

You are targetting ES3, but the 'compact' notation is an ES2020 feature.

[mjpieters]

You are targetting ES3, but the 'compact' notation is an ES2020 feature.

I'm not. I don't know why the playground link, when opened, indeed shows 'ES3', but the config as included in the issue uses "target": "Latest" and locally I have "target": "esnext". Looks like this is a playground bug as the playground URL includes target=99; I reported it to the TypeScript-Website repo.

I've also linked to the source code for esnext.intl.d.ts here, where you can see that the NumberFormatPartTypes type definition is clearly missing "compact" as an option.

[mjpieters]

I've found a few more missing types:

• 'unknown'
• 'exponentSeparator'
• 'exponentMinusSign'
• 'exponentInteger'

(also reported to MDN).

[andrewbranch]

Fixed by #42066