4 ms·

Show HN: I built an extension of JavaScript in a day

• m90 12y ago
  You'll have a hard time fighting GitHub classifying `.djs` as DogeScript.... Nevertheless, good luck with the project and everything.
• tshadwell 12y ago
  By the way, `typeof X === 'undefined'` doesn't need to be used for variable names that exist such as arguments, you can use X == undefined without opportunity for failure.
  • chmod775 12y ago
    Thank you! I'll fix it asap.
  • woogley 12y ago
    Technically, all edge cases considered, `typeof` is the only fool-proof check, since you can't override the string constant `'undefined'` but the `undefined` identifier is fair game. Here is one such edge case: (function () { var undefined = true; return (function foo(x) { return x === undefined; }()); }()); // false Language pedantry aside, browsers these days will freeze `window.undefined` so you'd have to shoot yourself in your own scope ;)
    • tshadwell 12y ago
      if you're that determined to shoot yourself in the foot you might as well rebind valueOf
• arknave 12y ago
  Looks like the readme example doesn't work. I didn't compile the djs sayHello function to verify it matches the given javascript, but running sayHello("nyc") spits out Hello to undefined, nyc You didn't tell me your age When I'd assume you wanted Hello to nyc, Tim You didn't tell me your age
  • chmod775 12y ago
    The first argument is the name, the second is city. If you give a third, the second will be your age and the third your city. Example: sayHello('Andreas', 'Berlin') sayHello('Andreas', 21, 'Berlin')
• dmitrig01 12y ago
  1. Instead of implementing it in vanilla JavaScript, consider creating a Sweet.js macros (or series of macros), so it can be used with other flavors of JS as well (e.g. JSX, etc) 2. On the async functions – what happens if you put an async function inside a conditional? This is effectively solved by ES6's yield + co or an equivalent. 3. A nitpick, but, is there a way to create static functions on classes? E.g. Car.x instead of Car.prototype.x?
  • chmod775 12y ago
    1. uh... oh 2. I'm not sure if I understand your correctly, but it should work if you wrap it in (). I actually have that very same example in 'broken.js' [0] 3. Sure. As you can write normal JavaScript, just use: Car.x = (arg){ //etc } The ':' operator is supposed to be a shortcut for X.prototype.Y [0]: https://github.com/binlain/designtojs/blob/master/test/broken.djs https://github.com/binlain/designtojs/blob/master/test/broke...
    • dmitrig01 12y ago
      Sorry, should have clarified on 2. As an expansion of one of the examples given: loadAndPrintFile: (contents) { if (!contents) { fs.readFile() -> (error!, contents) } console.log(contents); } i.e., expected behavior would be as if readFile was not an async function. I'm asking because I built something similar (though it only worked with promises, not general async functions), and I'm curious to compare approaches :-) - mine is a sweet.js macro: http://pastie.org/9410315 http://pastie.org/9410315 (uses https://github.com/petkaantonov/bluebird https://github.com/petkaantonov/bluebird and https://github.com/BranchMetrics/promise-accum https://github.com/BranchMetrics/promise-accum). The basic syntax would be: task { item1 <- LoadItem(1); item2 <- LoadItem(item1.foreign_key); ret <- DoSomethingWithItems(item1, item2); }
      • chmod775 12y ago
        The JavaScript result of your example looks like this: (again, beautified because DesignToJS crams everything in one line to preserve the line numbers of your actual code): function loadAndPrintFile(contents) { if (!contents) { fs.readFile(function(error, contents){ if(error !== null && error !== undefined){ return error; } }); } console.log(contents); } If you omit the function body, it will only expand to the end of the current logical 'context' (or whatever it's called) I'd suggest writing it like this in DesignToJS: loadAndPrintFile: (contents! console.log) { fs.readFile() -> (error!, contents! console.log) } Result looks like this: function loadAndPrintFile(contents) { if(contents !== null && contents !== undefined){ return console.log(contents); } fs.readFile(function(error, contents){ if(error !== null && error !== undefined){ return error; } if(contents !== null && contents !== undefined){ return console.log(contents); } }); } Edit: I just submitted a patch that avoids unnecessary binding of 'this' if 'this' is not actually used.
• pearknob 12y ago
  Firstly, congratulations on making something useful in one day. Great job. I skimmed over the documentation/examples and this is excellent.
• phpnode 12y ago
  This looks cool but I think your syntax clashes with JS's standard LabeledStatement
  • chmod775 12y ago
    Good thinking, but I already do detect and handle that case correctly. There's a test case in 'test/namedThings.(d)js'