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Writing njs code using TypeScript definition files

Compiling TypeScript definition files API checks and autocompletions Writing njs type-safe code

TypeScript is a typed superset of JavaScript that compiles to plain JavaScript.

TypeScript supports definition files that contain type information of existing JavaScript libraries. This enables other programs to use the values defined in the files as if they were statically typed TypeScript entities.

njs provides TypeScript definition files for its API which can be used to:

• Get autocompletion and API check in an editor
• Write njs type-safe code

Compiling TypeScript definition files

$ git clone https://github.com/nginx/njs
$ cd njs && ./configure && make ts
$ ls build/ts/
njs_core.d.ts
njs_shell.d.ts
ngx_http_js_module.d.ts
ngx_stream_js_module.d.ts

API checks and autocompletions

Put *.d.ts files to a place where you editor can find it.

test.js:

/// <reference path="ngx_http_js_module.d.ts" />
/**
 * @param {NginxHTTPRequest} r
 * */
function content_handler(r) {
    r.headersOut['content-type'] = 'text/plain';
    r.return(200, "Hello");
}

Writing njs type-safe code

test.ts:

/// <reference path="ngx_http_js_module.d.ts" />
function content_handler(r: NginxHTTPRequest) {
    r.headersOut['content-type'] = 'text/plain';
    r.return(200, "Hello from TypeScript");
}

TypeScript installation:

# npm install -g typescript

TypeScript compilation:

$ tsc test.ts
$ cat test.js

The resulting test.js file can be used directly with njs.