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205import { describe, it, expect } from 'vitest';
import { webpack, type Stats } from 'webpack';
import { build as tsdownBuild } from 'tsdown';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';
import { mkdtempSync, writeFileSync, rmSync } from 'node:fs';
import { tmpdir } from 'node:os';
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
async function runWebpack(
entry: string,
loaderPath: string
): Promise<{ output: string; stats: Stats }> {
await tsdownBuild({
logLevel: 'error',
});
// replace /src with /dist in loaderPath
loaderPath = loaderPath.replace('/src/', '/dist/');
// replace .ts with .js in loaderPath
loaderPath = loaderPath.replace('.ts', '.js');
return new Promise((resolve, reject) => {
const compiler = webpack({
mode: 'development',
entry,
output: {
path: join(tmpdir(), 'webpack-test-output'),
filename: 'bundle.js',
},
module: {
rules: [
{
test: /\.css$/,
use: [
'style-loader',
'css-loader',
{
loader: loaderPath,
},
],
},
],
},
optimization: {
minimize: false,
},
plugins: [
{
apply(compiler) {
compiler.hooks.emit.tap('CaptureOutputPlugin', (compilation) => {
const asset = compilation.assets['bundle.js'];
if (asset) {
if (typeof asset.source === 'function') {
capturedOutput = asset.source().toString();
return;
}
if (typeof asset.buffer === 'function') {
capturedOutput = asset.buffer().toString('utf-8');
return;
}
throw new Error('Unknown asset source type');
}
});
},
},
],
});
let capturedOutput = '';
if (!compiler) {
reject(new Error('Failed to create webpack compiler'));
return;
}
compiler.run((err, stats) => {
if (err) {
reject(err);
return;
}
if (!stats) {
reject(new Error('No stats returned'));
return;
}
const info = stats.toJson();
if (stats.hasErrors()) {
reject(new Error(info.errors?.[0]?.message || 'Unknown error'));
return;
}
if (!capturedOutput) {
reject(new Error('Failed to capture bundle output'));
return;
}
compiler.close(() => {
resolve({ output: capturedOutput, stats });
});
});
});
}
function createTempFiles(cssContent: string, query: string): { jsFile: string; tempDir: string } {
const tempDir = mkdtempSync(join(tmpdir(), 'scoped-rem-test-'));
const cssFile = join(tempDir, `test.css`);
const jsFile = join(tempDir, `entry.js`);
writeFileSync(cssFile, cssContent);
const importStatement = `import './test.css${query}';`;
writeFileSync(jsFile, importStatement);
return { jsFile, tempDir };
}
describe('scoped-rem-loader', () => {
it('should export a webpack loader function', async () => {
const loader = await import('../src/index.js');
expect(loader.default).toBeDefined();
expect(typeof loader.default).toBe('function');
});
it('should have proper loader signature', async () => {
const loader = await import('../src/index.js');
expect(typeof loader.default).toBe('function');
expect(loader.default.length).toBeGreaterThan(0);
});
});
describe('webpack integration tests', () => {
const loaderPath = join(__dirname, '../src/index.ts');
it('should transform rem units with rem-scoped query', async () => {
const inputCss = `.component { font-size: 1.2rem; margin: 0.5rem; }`;
const { jsFile, tempDir } = createTempFiles(inputCss, '?rem-scoped&rootval=26.6667vw');
try {
const { output } = await runWebpack(jsFile, loaderPath);
expect(output).toContain('--rem-relative-base');
expect(output).toContain('26.6667vw');
expect(output).toContain('calc(1.2 * var(--rem-relative-base))');
expect(output).toContain('calc(0.5 * var(--rem-relative-base))');
} finally {
rmSync(tempDir, { recursive: true, force: true });
}
});
it('should not transform without rem-scoped query', async () => {
const inputCss = `.component { font-size: 1.2rem; }`;
const { jsFile, tempDir } = createTempFiles(inputCss, '');
try {
const { output } = await runWebpack(jsFile, loaderPath);
expect(output).toContain('1.2rem');
expect(output).not.toContain('calc(');
expect(output).not.toContain('--rem-relative-base');
} finally {
rmSync(tempDir, { recursive: true, force: true });
}
});
it('should support custom variable names and selectors', async () => {
const inputCss = `.component { font-size: 1.5rem; }`;
const { jsFile, tempDir } = createTempFiles(
inputCss,
'?rem-scoped&rootval=10vw&varname=custom-base&varselector=.my-component'
);
try {
const { output } = await runWebpack(jsFile, loaderPath);
expect(output).toContain('--custom-base: 10vw');
expect(output).toContain('calc(1.5 * var(--custom-base))');
expect(output).not.toContain('--rem-relative-base');
expect(output).toContain('.my-component { --custom-base: 10vw');
} finally {
rmSync(tempDir, { recursive: true, force: true });
}
});
it('should not generate variable declaration if rootval is missing', async () => {
const inputCss = `.component { font-size: 2rem; }`;
const { jsFile, tempDir } = createTempFiles(inputCss, '?rem-scoped&varname=base-no-rootval');
try {
const { output } = await runWebpack(jsFile, loaderPath);
expect(output).toContain('calc(2 * var(--base-no-rootval))');
expect(output).not.toContain('--base-no-rootval:');
expect(output).not.toContain('{ --base-no-rootval:');
} finally {
rmSync(tempDir, { recursive: true, force: true });
}
});
});