import assert from 'node:assert/strict';

import { readdir } from 'node:fs/promises';

import { replaceInFile } from '../../utils/fs';

import { execWithEnv, ng } from '../../utils/process';

export default async function () {

// Add lazy routes.

await ng('generate', 'component', 'lazy-a');

await ng('generate', 'component', 'lazy-b');

await ng('generate', 'component', 'lazy-c');

await replaceInFile(

'src/app/app.routes.ts',

'routes: Routes = [];',

`routes: Routes = [

{

path: 'lazy-a',

loadComponent: () => import('./lazy-a/lazy-a').then(m => m.LazyA),

},

{

path: 'lazy-b',

loadComponent: () => import('./lazy-b/lazy-b').then(m => m.LazyB),

},

{

path: 'lazy-c',

loadComponent: () => import('./lazy-c/lazy-c').then(m => m.LazyC),

},

];`,

);

// Build without chunk optimization

await execWithEnv('ng', ['build', '--output-hashing=none'], {

...process.env,

NG_BUILD_OPTIMIZE_CHUNKS: 'false',

});

const unoptimizedFiles = await readdir('dist/test-project/browser');

const unoptimizedJsFiles = unoptimizedFiles.filter((f) => f.endsWith('.js'));

// Build with chunk optimization

await execWithEnv('ng', ['build', '--output-hashing=none'], {

...process.env,

NG_BUILD_OPTIMIZE_CHUNKS: '1',

});

const optimizedFiles = await readdir('dist/test-project/browser');

const optimizedJsFiles = optimizedFiles.filter((f) => f.endsWith('.js'));

// Check that the number of chunks is reduced but not all combined

assert.ok(

optimizedJsFiles.length < unoptimizedJsFiles.length,

`Expected chunk count to be less than ${unoptimizedJsFiles.length}, but was ${optimizedJsFiles.length}.`,

);

assert.ok(

optimizedJsFiles.length > 1,

`Expected more than one chunk, but found ${optimizedJsFiles.length}.`,

);

}