The promise and the hack

This lightning talk presents one pattern to bind components actions in a tree with the use of deferreds objects.

1. The promise and the hack Some names and identifying details have been changed to protect the privacy of individuals. @bobylito ParisJS # 43
2. – @bobylito “Pour bien apprendre quelque chose, il faut en abuser”
3. Promises
4. Promises call1( params, function( res0 ){ call2( res0, function( res1 ){ //.... THIS IS HELL!! } ); } );
5. Promises call1( } ); call1( params ).then( call2 ) .then( function peace(){ // At last } );
6. Deferred objects • The origin of all promises • Remote controls of the promises
7. Deferred objects • Get a promise from it • Set the state of the promise state with reject (error etc) or resolve (value)
9. var actions = { colorIt : Q.defer() } actions.colorIt.fCall( theNewColor ); var self = this; actions.colorIt.then( function( colorItF ){ self.colorOtherComponent = colorItF; } ); actions.colorIt.resolve( function colorBgComponentA( color ){ //... PROFIT! } )
10. Benefits • No order required during components initialisation • Documentation of all the messages that can be exchange in the app • The root can check if all the actions are resolved
11. Thanks! • @bobylito (follow me ;) ) • Partners in crime : @42loops && @greweb • Check zanimo, qAjax, qAnimationFrame