Sources Management

JavaScript Sources Location

The JavaScript sources of an application must be located in the project folder src/main/js. All JavaScript files (*.js) found in this folder, at any level, are processed.

JavaScript Sources Load Order

When several JavaScript files are found in the sources folder, they are loaded in alphabetical order of their relative path. For example, the following source files:

src
└── main
    └── js
        ├── components
        │   ├── component1.js
        │   └── component2.js
        ├── ui
        │   └── widgets.js
        ├── app.js
        ├── feature1.js
        └── feature2.js

are loaded in this order:

app.js
components/component1.js
components/component2.js
feature1.js
feature2.js
ui/widgets.js

JavaScript Sources Load Scope

All the code of the JavaScript source files are loaded in the same scope. It means a variable or function defined in a source file can be used in another one if it has been loaded first. In this example:

src/main/js/lib.js

function sum(a, b) {
    return a + b;
}

src/main/js/main.js

print("5 + 3 = " + sum(5, 3));

the file src/main/js/lib.js is loaded before src/main/js/main.js so the function sum can be used in src/main/js/main.js.

JavaScript Sources Processing

JavaScript sources need to be processed before being executed. This processing is done in the following cases:

when building the project with MMM.
when developing the project in MicroEJ SDK. The MicroEJ SDK detects any change in JavaScript sources folder (addition/update/deletion) to trigger the processing.