file.js

const environment = {
    type: 'prod',
    variables: {
        api: 'some-url',
        port: '8080'
    }
}

const { 
 type: envType, // we extract "type" and call it "envType" here
 variables: { api: envApi, ...envRest } // we extract "api" as "envApi" and add the rest into "envRest"
} = environment;

console.log(envType); // 'prod'
console.log(envApi); // 'some-url'
console.log(envRest); // {port: '8080'}