The difference between AMD and CMD

On the difference between the two online can search out a bunch of articles, a simple summary

The most obvious difference is that the process of dependency is different when the module is defined.

1, AMD respected the reliance on the front, in the definition of the module must declare its dependent modules
2, CMD respected the nearest dependence, only in the use of a module and then go to require
This difference has the pros and cons, only the grammatical gap, and Requirejs and SEAJS support each other's writing

The biggest difference between AMD and CMD is that the timing of the dependent modules is different, not the timing or the way of loading.

Many people say that Requirejs is an asynchronous loading module, SEAJS is a synchronous loading module, so understanding is actually not accurate, in fact, the loading module is asynchronous, but AMD relies on the front, JS can easily know who the dependent module is, immediately loaded, and cmd nearest to the dependency, Need to use to turn the module into a string to understand the dependencies of those modules, which is also a lot of people criticized the CMD, sacrificing performance to bring the convenience of development, in fact, the parsing module time is short enough to ignore

Why do we say that the two difference is dependent on the timing of the module execution, why many people think that ADM is asynchronous, CMD is synchronous (except for the name of the reason ...). ）

The same is the asynchronous loading module, AMD after the loading module completes the module will be executed, all modules loaded after execution will enter the require callback function, the execution of the main logic, the effect is dependent on the module execution sequence and writing order is not necessarily consistent, see the network speed, which first downloaded down, which first executed, But the master logic must be executed after all dependent loads have been completed.

CMD does not execute after loading a dependent module, just download it, after all the dependent modules are loaded to enter the main logic, when encountering the Require statement to execute the corresponding module, so that the module execution sequence and writing order is exactly the same

This is also a lot of people say that the AMD user experience is good, because there is no delay, the dependency module executes ahead of time, cmd performance is good, because only the user needs to execute the reason