A parser and formatter for TypeScript declarations that outputs HM-style type signatures.
Available in editors via typescript-tshm-plugin.
Usage: tshm (filepath | (-e|--eval code)) [-f|--forall string] [-r|--readonly]
[-a|--all]
A parser and formatter for TypeScript declarations that outputs HM-style type
signatures.
Available options:
-h,--help Show this help text
-v,--version Output version
filepath Read and evaluate the file at the provided path
-e,--eval code Evaluate input code directly. Alternatively the code
can be supplied directly via stdin without this
option
-f,--forall string Specify a string to be used to express universal
quantification, for example "forall" or "∀". If set
to "none" or omitted, no universal quantification
will be displayed
-r,--readonly Display readonly modifiers
-a,--all Output all declarations regardless of whether or not
they're exported. Useful in tandem with --eval
Example:
$ echo "type Option<A> = None | Some<A>" | tshm -a
type Option a = None | Some a
$ echo "type Milliseconds = Newtype<{ readonly Milliseconds: unique symbol }, number>" | tshm -a
newtype Milliseconds = number
$ echo "declare const invertAll: <A>(f: (x: A) => string) => (x: Record<string, A>) => Record<string, string[]>" | tshm -a
invertAll :: (a -> string) -> Record string a -> Record string (Array string)
$ echo "declare const withIndex: <A, B, C>(
f: (g: (x: A) => B) => (ys: A[]) => C[]
) => (g: (i: number) => (x: A) => B) => (ys: A[]) => C[]" | tshm -a --forall ∀
withIndex :: ∀ a b c. ((a -> b) -> Array a -> Array c) -> (number -> a -> b) -> Array a -> Array c
The parser does not perform any sort of correctness checking beyond its ability to understand the syntax.
Should an invalid input be provided the program will fail with the appropriate exit code, enabling the use of tshm in shell pipelines.
Messages are always printed upon failure. Should the failure be due to a parser error, the raw error is printed to the console to assist in debugging.
A patcher for docs-ts output is also provided.
Prebuilt binaries are produced via CI on each release. An official AUR package is available at tshm-bin.
tshm is currently developed against GHC 9.2.7.
The codebase is split up into two parts, lib/ and src/, representing the internal library and the CLI interface respectively.
The library handles everything from parsing to compilation. During parsing we parse the input into an initial AST, performing no correctness checking beyond what's needed to reliably parse any valid TypeScript declaration. Prior to compilation we perform a reconciliation step in which semantics that couldn't be handled by the parser are taken care of. Compiling is essentially the parsing process in reverse, taking a syntactic token and outputting a string representing it. The library has a number of unit tests defined for each the parser, reconciler, and compiler.