typescript-simple

Simple API to compile TypeScript code string to JavaScript. That's all!

Description

typescript-simple provides just one method that accepts TypeScript code string and returns JavaScript code.

Why?

• TypeScript v1.4 doesn't have simple TS string to JS string API
• TypeScript v1.5 has ts.transpile(), but it cannot generate source map
• TypeScript v1.6+ has ts.transpile() with source map, but it always ignores type checking

Versioning

• typescript-simple v1.x.x uses TypeScript v1.4
• typescript-simple v2.x.x uses TypeScript v1.5
• typescript-simple v3.x.x uses TypeScript v1.6
• typescript-simple v4.x.x uses TypeScript v1.7
• typescript-simple v5.x.x uses TypeScript v1.8

Note: typescript-simple updates the major version for TypeScript's minor update including breaking changes.

Install

$ npm install typescript-simple

Usage

Simple usage (default target is ES5).

var tss = require('typescript-simple');
var js = tss('var n: number = 1;');
console.log(js); // 'var n = 1;'

If the code causes errors, typescript-simple throws errors.

try {
    var js = tss('var n: number = "str";');
} catch (e) {
    console.error(e); // Error: L1: Type 'string' is not assignable to type 'number'.
}

Compiler Options

Specify CompilerOptions at 2nd argument.

var js = tss('var n: number = 1;', {noImplicitAny: true});

Make repeated compilation faster

tss() with options is not best-performance-method to be executed many times. Use TypeScriptSimple class for this purpose.

var TypeScriptSimple = require('typescript-simple').TypeScriptSimple;
var tss = new TypeScriptSimple({target: ts.ScriptTarget.ES6, noImplicitAny: true});
var js1 = tss.compile('var n: number = 1;');
var js2 = tss.compile('var s: string = "foo";');

Ignore semantic errors

If you don't need TypeScript semantic error and just want the result code, give 2nd argument of the constructor false.

var tss = new TypeScriptSimple({target: ts.ScriptTarget.ES6}, false);
var js = tss.compile('var n: string = 1;'); // an error is not thrown.

Note: syntactic errors may be thrown.

JSX (.tsx)

• --jsx=preserve

var jsx = tss.compile('var foo: any = <Foo />;', {jsx: ts.JsxEmit.Preserve});
console.log(jsx); // 'var foo = <Foo />;'

• --jsx=react

var tss = new TypeScriptSimple({jsx: ts.JsxEmit.React}, false);
var js = tss.compile('var foo: any = <Foo />;');
console.log(js); // 'var foo = React.createElement("Foo", null);'

Note: Ignore semantic errors if you use JsxEmit.React.

Source map

Inline source map is available.

var tss = new TypeScriptSimple({sourceMap: true});
var js = tss.compile('var n: number = 1;', 'path/to/file.ts');

Output:

var n = 1;
//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uI...

Note: The path to file doesn't need to be an actual file. We just copy the contents of the passed in ts string into the inline sourceMap and make it look like the js is coming from a ts file at that file path.

Limitations

typescript-simple cannot compile multiple source files.

API

See index.d.ts.

Contributors

• @basarat

License

MIT License: Teppei Sato <[email protected]>