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