async/await with TypeScript

This example demonstrates the use of async/await using TypeScript v1.9-dev, Node.js v6 and Visual Studio Code v1.0;

$ node lib/await.js
1
2
3
Error: throw error to showcase source map support.
    at /async_await_typescript/lib/await.ts:21:9
    at undefined.next (native)
    at fulfilled (/async_await_typescript/lib/await.js:4:58)

Manually compile using gulp. To run tsc directly, use tsc -p .

Install dependencies

• Download Visual Studio Code 1.0 or later
• node -v Ensure node is v6 or later
• npm install . Install deps defined in package.json

Visual Studio Code Integration

• File ▸ Auto Save Enable auto save.
• Gulp tasks are auto detected and made available in the task list. On a Mac Shift + Command + P ▸ Run Task ▸ Press Enter then select Watch.
• Watch automatically compiles TypeScript according to the gulpfile rules.

Directory Overview

.
├── .vscode
│   ├── launch.json
│   └── settings.json
├── lib
│   ├── await.js
│   └── await.js.map
├── node_modules
├── ts
│   └── await.ts
├── .gitignore
├── gulpfile.js
├── jsconfig.json
├── package.json
├── readme.md
├── tsconfig.json

• .vscode/settings.json - Settings for Visual Studio Code. Code ▸ Preferences ▸ Workspace Settings to change.
• .vscode/launch.json - Launch Configuration that enables debugging in Visual Studio code.
• lib/await.js - Output from TypeScript. lib is a mix between ES6 and ES5. This code runs on node v6 or better.
• lib/await.js.map - Source maps allows tracing failures back to line numbers in the original typescript files.
• node_modules - The dependencies defined in package.json
• ts/await.ts - TypeScript source files which are automatically transpiled on save by typescript.
• .gitignore - Standard git ignore file.
• gulpfile.js - Gulp build system used to setup source maps, babel, and typescript.
• jsconfig.json - Visual Studio Code config file that defines the version of JavaScript used by the editor.
• package.json - Standard npm package config that defines dependencies and other metadata useful when publishing to npm.
• readme.md - The document you're currently reading.
• tsconfig.json - The typescript compiler options.

Workflow

• Node is still missing many ES6 features.

node --v8-options | grep "in progress"

Node lacks support for ES6 modules because v8 hasn't implemented them As a result module type commonjs is used in tsconfig.json.

• typescript Transpiles ES 7 to ES 6
• node.js Runs ES 6/5 hybrid

TypeScript offers granular targeting via the lib compiler option specified in tsconfig.

Debugging

Visual Studio Code supports debugging TypeScript with source map support.

Credits

• Thanks to @ivogabe for blogging about using typescript with babel
• Thanks to @Deathspike for posting an async example