The modern way to write TypeScript.
- Documentation
- Design Philosophy
- Civet Playground
- Civet VSCode Extension
- Discord Server
- Plugins for Vite, esbuild, Astro, Rollup, Webpack, Rspack ESM/CJS loader, Babel, Gulp, Bun
- Starter templates for Solid and Solid Start
# Install
npm install -g @danielx/civet
# Run Civet code directly in a REPL
civet
# Transpile typed Civet code into TypeScript in a REPL
civet -c
# Compile Civet source file to TypeScript
civet < source.civet > output.ts
# Execute a .civet script
civet source.civet ...args...
# Execute a .civet source file in node
node --import @danielx/civet/register source.civet
ts, {CompilerOptions} from typescript
DefaultCompilerOptions : CompilerOptions :=
allowNonTsExtensions: true
allowJs: true
target: ts.ScriptTarget.Latest
moduleResolution: ts.ModuleResolutionKind.NodeJs
module: ts.ModuleKind.CommonJS
allowSyntheticDefaultImports: true
experimentalDecorators: true
fileCache : Record<string, any> := {}
createCompilerHost := (options: CompilerOptions, moduleSearchLocations : string[]) ->
fileExists := (fileName: string) : boolean ->
fileCache[fileName]?
readFile := (fileName: string) ->
fileCache[fileName]Civet is essentially a tasteful superset of TypeScript.
See the documentation for examples of these and other features.
- Pattern matching (based on TC39 proposal)
switchcan match patterns like[{type: "text", name}, ...rest]
- Pipe operator (based on F# pipes, Hack pipes and the TC39 proposal)
data |> Object.keys |> console.logequivalent toconsole.log(Object.keys(data))- Use single-argument arrow functions or
&shorthand to specify how to use left-hand side |> await,|> yield, and|> return(at end) for wrapping left-hand side with that operation
- Short function block syntax like Ruby symbol to proc, Crystal, Elm record access
- Access:
x.map &.nameorx.map .name→x.map(a => a.name) - Nested access + slices:
x.map &.profile?.name[0...3]→x.map(a => a.profile?.name.slice(0, 3)) - Function call:
x.map &.callback a, b→x.map($ => $.callback(a, b)) - Unary operators:
x.map !!&→x.map($ => !!$) - Binary operators:
x.map &+1→x.map($ => $+1)
- Access:
- Object literal shorthand
{foo()}→{foo: foo()},{props.foo}→{foo: props.foo}{`${x}${y}`: z}→{[`${x}${y}`]: z}data.{x,y}ordata{x,y}→{x: data.x, y: data.y}- Flagging shorthand based on from LiveScript:
{+debug, -live, !verbose}→{debug: true, live: false, verbose: false}
- Custom infix operators from any two-argument function
doexpressions,ifexpressions,forexpressions
- Const assignment shorthand:
a := b→const a = b,{a, b} := c→const {a, b} = c - Let assignment shorthand:
a .= b→let a = b - Typed versions of above:
a: number .= 5→let a: number = 5(but note thata: number = 5is the object literal{a: (number = 5)}). @#id→this.#idshorthand for private identifiersimportshorthand:x from ./x→import x from "./x"- Dynamic
importshorthand:import './x'not at top level (e.g.await import './x'or inside a function) →import('./x') - Optional import rename syntax that corresponds to destructuring rename
import {x: y} from "./z"→import {x as y} from "./z". You can still useasto be compatible with existing ES imports. exportshorthand:export x, y→export {x, y}- Triple backtick Template Strings remove leading indentation for clarity
- Class constructor shorthand
@( ... ) - ClassStaticBlock
@ { ... } <asextendsshorthand///Block RegExp like Python re.X
Inspired by solid-dsl discussions and jsx spec issues
- Indentation: instead of explicitly closing
<tag>s or<>s, you can indent the children and Civet will close your tags for you - Multiple adjacent elements and/or fragments get automatically combined into a fragment.
- Arrow function children do not need to be wrapped in braces
(assuming they are not preceded by text); this is unambiguous because
>isn't valid JSX text. For example,<For> (item) => ...(where function body can be indented). #fooshorthand forid="foo"; also#"foo bar",#`foo ${bar}`,#{expr}.fooshorthand forclass="foo"(but must be at least one space after tag name); also.foo.bar,."foo bar",.`foo ${bar}`,.{expr}"civet react"flag usesclassNameinstead ofclass
+fooshorthand forfoo={true},-foo/!fooshorthand forfoo={false}- Any braced object literal can be used as an attribute:
{foo}→foo={foo},{foo: bar}→foo={bar},{...foo}remains as is; methods and getters/setters work too. - Attribute
...fooshorthand for{...foo} - Attribute values without whitespace or suitably wrapped
(parenthesized expressions, strings and template strings,
regular expressions, array literals, braced object literals)
do not need braces:
foo=bar→foo={bar},count=count()→count={count()},sum=x+1→sum={x+1},list=[1, 2, 3]→list={[1, 2, 3]} - Attributes can use computed property names:
[expr]={value}→{...{[expr]: value}} "civet solid"flag adds correct types for JSX elements and fragments. Use"civet solid client"(default) for client-only code,"civet solid server"for server-only code (SSR only), or"civet solid client server"for isomorphic code that runs on client and server (SSR + hydration).- XML comments:
<!-- ... -->→{/* ... */}
- Auto-rewrite
.[mc]ts→.[mc]jsin imports (workaround for: microsoft/TypeScript#37582) :=readonly class field initializerclass A x := 3
class A { readonly x = 3 }
- Proposal: Typed Destructuring
- Proposal: Dot Notation for Types
- Proposal: Module Interfaces microsoft/TypeScript#38511
- TODO: Type Declaration Shorthand
- Implicit returns, even for multi-statement functions
(avoid by specifying a
voidreturn type, adding a trailing;or explicitreturn, or via the directive"civet -implicitReturns") - Disallow no parens on single argument arrow function.
x => ...must become(x) => ...The reasoning isx -> ...=>x(function() ...)in CoffeeScript and having->and=>behave more differently than they already do is bad. Passing an anonymous function to an application without parens is also convenient. for(i of x) ...defaults to const declaration →for(const i of x) ...- Disallow comma operator in conditionals and many other places.
if x, yis not allowed. Butfor i = 0, l = a.length; i < l; i++, i *= 2is allowed. - Comma operator in
case/wheninstead becomes multiple conditions. - Numbers can't end with a dot (otherwise would be ambiguous with CoffeeScript slices
y[0..x]). This also implies that you can't access properties of numbers with1..toString()use1.toString()instead. When exponent follows a dot it is treated as a property access since an exponent could be a valid property1.e10→1..e10. The workaround is to add a trailing zero1.0e10or remove the dot before the exponent1e10. - Additional reserved words
and,or,loop,until,unless - Experimental decorator syntax is
@@instead of@because@is premium real estate and@id→this.id, and@is also static fields/methods, etc.@@classDecorator class X @@methodDecorator method() {} wheninside switch automatically breaks and adds block scope.elseinside switch adds block scope.- No whitespace between unary operators and operands. Mandatory whitespace between condition and ternary
?ex.x ? a : bsincex?is the unary existential operator. - Labels written
:label(except for special case$:for Svelte)
- Shebang line is kept unmodified in output
#!./node_modules/.bin/ts-node console.log "hi"
Take a look at this detailed Civet // CoffeeScript comparision
You can specify "civet" prologue directives to increase
compatibility with ECMAScript/TypeScript:
| Configuration | What it enables |
|---|---|
| -implicit-returns | turn off implicit return of last value in functions |
Put them at the top of your file:
"civet -implicit-returns"
Your can separate multiple options with spaces.
TypeScript only allows importing .ts files as .js. Deno follows ESM and requires importing files with the correct extension.
Civet automatically rewrites imports to work around this issue in TS.
When Civet detects it is running in Deno rewriting imports is turned off. If for some reason Civet fails to detect running in Deno you can turn off rewriting imports manually with these configuration options:
| Configuration | What it enables |
|---|---|
| -rewrite-ts-imports | disable rewriting .ts -> .js in imports |
| deno | currently just disables rewriting imports but could add more deno specific options in the future |
The "civet" prologue directive can also specify the following options:
| Configuration | What it enables |
|---|---|
| rewrite-civet-imports=.ext | Rewrite import "file.civet" to import "file.ext" |
| tab=NNN | treat tab like NNN spaces (default=1) |
For example, "civet tab=2" or "civet tab=4" lets you mix tabs and spaces
in a file and be treated like they'd render in VSCode with editor.tabSize
set accordingly.
You have now been convinced that Civet is right for your current/next project. Here is how to set up your environment to get productive right away and have a Good Time℠.
Code coverage with c8 "just works" thanks to their source map integration and Civet's source maps.
Currently Civet's ESM loader depends on ts-node
package.json
"scripts": {
"test": "c8 mocha",
...
},
"c8": {
"extension": [
".civet"
]
},
"mocha": {
"extension": [
"civet"
],
"loader": [
"ts-node/esm",
"@danielx/civet/esm"
],
...
...ts-node must be configured with transpileOnly (it can't resolve alternative extensions). Also I think module needs to be at least ES2020 for the Civet ESM loader to work.
tsconfig.json
...
"ts-node": {
"transpileOnly": true,
"compilerOptions": {
"module": "ES2020"
}
}If you don't care for code coverage you can skip c8 (but it is so easy why not keep it?).
You can also add .js and .ts extensions if you want to mix and match! Even .coffee will work if you require coffeescript/register or add a loader for it.
Execute the tests
yarn testStep 4: Enjoy!
Use the alpha version of Civet Language Server
The language server provides syntax highlighting, completions, hover documentation, symbols outline, red squigglies, and go to definition.
Q? Why can't I just use the built-in VSCode TypeScript LSP?
A: VSCode's built in TypeScript LSP can't resolve non .ts/.js, not even with plugins. Maybe one day they'll allow for
plugins that let you adjust the resolver and insert a transpilation step but until then a separate language server is necessary.
Q? Sometimes the file outline disappears and the red squigglies are all in the wrong place and maybe a notification pops up about some kind of LSP error.
A: I'm sorry that happened to you but the Civet Language Server is still alpha and improving rapidly. Please let me know exactly what happened and I'll try to do better next time.
It may happen when there is a syntax error in your Civet file. You can check and see if it compiles using the CLI tool in the meantime.
Please do submit bug reports / feature requests.
I strongly recommend using esbuild for building / packaging your Civet project.
import esbuild from 'esbuild'
import civetPlugin from '@danielx/civet/esbuild-plugin'
esbuild.build({
...,
plugins: [
civetPlugin
]
}).catch(() => process.exit(1))It's super fast and works great!
If you are so inclined, you can sponsor Civet on Open Collective.
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