Now Typescript supports the creation of anonymous types using successive
`@param` lines in JSDoc:
```js
/**
* @param {object} o - has a string and a number
* @param {string} o.s - the string
* @param {number} o.n - the number
*/
function f(o) { return o.s.length + o.n; }
```
This is equivalent to the Typescript syntax `{ s: string, n: number }`,
but it allows per-property documentation, even for types that only need
to be used in one place. (`@typedef` can be used for reusable types.)
If the type of the initial `@param` is `{object[]}`, then the resulting
type is an array of the specified anonymous type:
```js
/**
* @param {Object[]} os - has a string and a number
* @param {string} os[].s - the string
* @param {number} os[].n - the number
*/
function f(os) { return os[0].s; }
```
Finally, nested anonymous types can be created by nesting the pattern:
```js
/**
* @param {Object[]} os - has a string and a number
* @param {string} os[].s - the string
* @param {object} os[].nested - it's nested because of the object type
* @param {number} os[].nested.length - it's a number
*/
function f(os) { return os[0].nested.length; }
```
Implementation notes:
1. I refactored JSDocParameterTag and JSDocPropertyTag to
JSDocPropertyLikeTag and modified its parsing to be more succinct. These
changes make the overall change easier to read but are not strictly
required.
2. parseJSDocEntityName accepts postfix[] as in `os[].nested.length`,
but it doesn't check that usages are correct. Such checking would be
easy to add but tedious and low-value.
3. `@typedef` doesn't support nested `@property` tags, but does support
`object[]` types. This is mostly a practical decision, backed up by the
fact that usejsdoc.org doesn't document nested types for `@typedef`.
TypeScript
TypeScript is a language for application-scale JavaScript. TypeScript adds optional types, classes, and modules to JavaScript. TypeScript supports tools for large-scale JavaScript applications for any browser, for any host, on any OS. TypeScript compiles to readable, standards-based JavaScript. Try it out at the playground, and stay up to date via our blog and Twitter account.
Installing
For the latest stable version:
npm install -g typescript
For our nightly builds:
npm install -g typescript@next
Contribute
There are many ways to contribute to TypeScript.
- Submit bugs and help us verify fixes as they are checked in.
- Review the source code changes.
- Engage with other TypeScript users and developers on StackOverflow.
- Join the #typescript discussion on Twitter.
- Contribute bug fixes.
- Read the language specification (docx, pdf, md).
This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.
Documentation
Building
In order to build the TypeScript compiler, ensure that you have Git and Node.js installed.
Clone a copy of the repo:
git clone https://github.com/Microsoft/TypeScript.git
Change to the TypeScript directory:
cd TypeScript
Install Gulp tools and dev dependencies:
npm install -g gulp
npm install
Use one of the following to build and test:
gulp local # Build the compiler into built/local
gulp clean # Delete the built compiler
gulp LKG # Replace the last known good with the built one.
# Bootstrapping step to be executed when the built compiler reaches a stable state.
gulp tests # Build the test infrastructure using the built compiler.
gulp runtests # Run tests using the built compiler and test infrastructure.
# You can override the host or specify a test for this command.
# Use host=<hostName> or tests=<testPath>.
gulp runtests-browser # Runs the tests using the built run.js file. Syntax is gulp runtests. Optional
parameters 'host=', 'tests=[regex], reporter=[list|spec|json|<more>]'.
gulp baseline-accept # This replaces the baseline test results with the results obtained from gulp runtests.
gulp lint # Runs tslint on the TypeScript source.
gulp help # List the above commands.
Usage
node built/local/tsc.js hello.ts
Roadmap
For details on our planned features and future direction please refer to our roadmap.