@offirgolan this is incredible work -- I'd love to see you continue to refine it and publish it as a package in some form.

👋 Hi there, its taken me a while to come back to this but I ended up completely overhauling the original implementation and created a types-only NPM package (icu-message-types).

import type { ICUMessageArguments, ICUMessageTags } from 'icu-message-types';

// Extract argument types
type Args0 = ICUMessageArguments<'Hello, {firstName} {lastName}!'>;
// Result: { firstName: string | number | boolean; lastName: string | number | boolean }

type Args1 = ICUMessageArguments<`{theme, select,
  light {The interface will be bright}
  dark {The interface will be dark}
  other {The interface will use default colors}
}`>;
// Result: { theme: 'light' | 'dark' | ({} & string) | ({} & number) | boolean | null }

// Extract tag names
type Tags = ICUMessageTags<'Click <link>here</link> to continue'>;
// Result: 'link'

Message Arguments

Additional Features

• Enhanced Value Types: Non-formatted arguments accept string | number | boolean | null for more flexible usage
• String Number Support: Numeric formats accept both number and template literal `${number}` types
• Comprehensive Select Matching: Select arguments with other clauses support string, number, boolean, and null
• Literal Type Transformation: Select keys are intelligently transformed (e.g., '123' becomes '123' | 123, 'true' becomes 'true' | true)
• Escaped content: Properly handles quoted/escaped text that shouldn't be parsed as arguments
• Nested messages: Supports complex nested structures
• Whitespace handling: Automatically strips whitespace, new lines, and tabs for improved parsing