Conditional code

The build tool’s static code analyzer is capable of removing dead code branches from the bundles it creates. Named conditional blocks are defined using Dojo framework’s has module and can be statically set to true or false through .dojorc and removed at build time.

main.ts

import has from '@dojo/framework/has';
if (has('production')) {
    console.log('Starting in production');
} else {
    console.log('Starting in dev mode');
}
export const mode = has('production') ? 'dist' : 'dev';

.dojorc

{
    "build-app": {
        "features": {
            "production": true
        }
    }
}

The above production feature will be set true for production builds (dist mode). The build system uses @dojo/framework/has to identify code as unreachable and remove those dead code branches from the build.

For example, the above code would be rewritten as:

static-build-loader output

import has from '@dojo/framework/has';
if (true) {
    console.log('Starting in production');
} else {
    console.log('Starting in dev mode');
}
export const mode = true ? 'dist' : 'dev';

The build tool’s dead branch removal would then remove the unreachable code.

Uglify output

console.log('Starting in production');
export const mode = 'dist';

Any features which are not statically asserted, are not re-written. This allows the code to determine at run-time if the feature is present.

Provided features

These features are provided by the build system to help identify a specific environment or mode of operation.