Yield

Lightning talk.
How Generators and Co can make asynchronous code look better.
Where to use it - from Co to Koa.

Transcript

1. yield
   @krzychukula
   

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2. function(){
   getUsername(function(err, username){
   getUser(username, function(err, user){
   //use username and user
   })
   })
   }
   

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3. function(){
   getUsername()
   .then(function (username) {
   return [username, getUser(username)];
   })
   .spread(function (username, user) {
   //use username and user
   });
   }
   

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4. co(function *(){
   var username = yield getUsername()
   var user = yield getUser(username)
   //use username and user
   })
   

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5. View Slide

6. Generators
   

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7. Co
   

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8. View Slide

9. co(function *(){
   var username = yield getUsername()
   var user = yield getUser(username)
   //use username and user
   })
   

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10. co(function *(){
    var username = “janek”
    var user = yield getUser(username)
    //use username and user
    })
    

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11. co(function *(){
    var username = “janek”
    var user = {id:”123”}
    //use username and user
    })
    

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12. Koa
    

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13. var koa = require('koa');
    var app = koa();
    app.use(function *(){
    this.body = 'Hello World';
    });
    app.listen(3000);
    

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14. function *list() {
    var res = yield books.find({});
    this.body = res;
    }
    

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15. nvm install v4
    

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16. Play with it!
    

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17. Thanks!
    krzychukula.blogspot.com
    

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