TypeScript 1.5.0-alpha Decorators

0 README

mkdir testDecorators
mkdir testDecorators
npm init
npm install [email protected] --save
node_modules/typescript/bin/tsc decorate.ts
node decorate.js
  false -> true
  true -> false

decorators.js

var __decorate = this.__decorate || function (decorators, target, key, value) {
    var kind = typeof (arguments.length == 2 ? value = target : value);
    for (var i = decorators.length - 1; i >= 0; --i) {
        var decorator = decorators[i];
        switch (kind) {
            case "function": value = decorator(value) || value; break;
            case "number": decorator(target, key, value); break;
            case "undefined": decorator(target, key); break;
            case "object": value = decorator(target, key, value) || value; break;
        }
    }
    return value;
};
var Debug = (function () {
    function Debug() {
    }
    Debug.assert = function (isTrue) {
        return isTrue;
    };
    Object.defineProperty(Debug, "assert", __decorate([flip], Debug, "assert", Object.getOwnPropertyDescriptor(Debug, "assert")));
    return Debug;
})();
Debug.assert(false);
Debug.assert(true);
function flip(target, key, value) {
    var _this = this;
    return {
        value: function (isTrue) {
            var result = value.value.apply(_this, [isTrue]);
            console.log(isTrue + " -> " + !result);
            return (!result);
        }
    };
}

decorators.ts

class Debug {  
    @flip 
    static assert( isTrue:boolean ):boolean {
        return isTrue
    }
}  

Debug.assert( false );
Debug.assert( true );

function flip(target: Function, key: string, value: any) {
    return {
        value: (isTrue: boolean) => {
            var result = value.value.apply(this, [isTrue]);
            console.log(isTrue + " -> " + !result)
            return (!result);
        }
    }
}

This is cool. Quick fixes: requires -t es5; the files are decorators.* but the instructions say decorate.ts; and I think you meant cd testDecorators on the second line. Thanks, Ted!