# SAPUI5 sap.ui.define and sap.ui.require

If you are a beginner of SAPUI5. you may be confused about the difference between sap.ui.define and sap.ui.require.

## Simple Conclusion

* sap.ui.define global namespace for your module and load dependent modules. (Define Module)
* sap.ui.require load dependent modules without declaring a namespace synchronously. (Call Module)

## Why

sap.ui.define and sap.ui .require are the same as in RequireJS. They are both provided to load module.

In javascript, There is no built-in module feature and there are 2 popular concept for modularization.

| Concept                                 | Feature                                                                                          |
| --------------------------------------- | ------------------------------------------------------------------------------------------------ |
| **CommonJS**                            | <ul><li>Node.js</li><li>Server Side</li><li>Compact Syntax</li><li>synchronous loading</li></ul> |
| **Asynchronous module definition(AMD)** | <ul><li>Browser</li><li>complicated syntax</li><li>asynchronous loading</li></ul>                |

Because SAPUI5 runs in the browser, sap use the AMD concept.(I doubt that...)

## Function Definition

### [Define](https://sapui5.hana.ondemand.com/#/api/sap.ui/methods/sap.ui.define)

```
sap.ui.define(sModuleName?, aDependencies?, vFactory, bExport?) : void
```

![](https://3536919124-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LaJGzuTd3rg88xS__Wx%2F-LasDzEwaorTcqjwH7C0%2F-LasGzp7xXkDOxR7bo4_%2Fimage.png?alt=media\&token=4883c8cb-a9d8-4066-8f3d-aaace827b920)

### [Require](https://sapui5.hana.ondemand.com/#/api/sap.ui/methods/sap.ui.require)

```
sap.ui.require(vDependencies, fnCallback?, fnErrback?) : any|undefined
```

![](https://3536919124-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LaJGzuTd3rg88xS__Wx%2F-LasDzEwaorTcqjwH7C0%2F-LasH9yJOVjfA65pEFkv%2Fimage.png?alt=media\&token=97004749-1b4e-4a0a-a317-35353792b3a0)

## Example

You can check this video for detail.

{% embed url="<https://www.youtube.com/watch?v=Yls62sVnins>" %}

{% embed url="<https://gist.github.com/04baf1dcb8fd2312a78fb60a0fe1afa5#file-definerequire-html>" %}

{% embed url="<https://gist.github.com/b4941202bf39c0843bb203ff8074e58c#file-somemodule-js>" %}

If you change the SomeModule's define to Require. It would load the file but you will get error because it's not defined.

![](https://3536919124-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LaJGzuTd3rg88xS__Wx%2F-LasDzEwaorTcqjwH7C0%2F-LasMD9jKvl2JEnFWc8G%2Fimage.png?alt=media\&token=fa2dca2a-e29a-4669-8bcd-daa7754c2435)


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