How to use @lwc/compiler - 7 common examples

process(src, filePath) {
        // Set default module name and namespace value for the namespace because it can't be properly guessed from the path
        const { code, map } = lwcCompiler.transformSync(src, filePath, {
            name: 'test',
            namespace: 'x',
            outputConfig: {
                sourcemap: true,
            },
        });

        // if is not .js, we add the .compiled extension in the sourcemap
        const filename = path.extname(filePath) === '.js' ? filePath : filePath + '.compiled';
        // **Note: .html and .css don't return valid sourcemaps cause they are used for rollup
        const config = map && map.version ? { inputSourceMap: map } : {};

        return babelCore.transform(code, { ...BABEL_CONFIG, ...config, filename });
    },
    getCacheKey(fileData, filePath, configStr, options) {

[
                    require.resolve('@babel/plugin-syntax-decorators'),
                    {
                        decoratorsBeforeExport: true
                    }
                ]
            ],
            presets: [require.resolve('@babel/preset-typescript')]
        })
        codeTransformed = code
    }

    // @ts-ignore
    const cb = this.async()

    compiler
        .transform(codeTransformed, resourcePath, {
            name: info.name,
            namespace: info.ns,
            outputConfig: compilerOutput,
            stylesheetConfig,
            experimentalDynamicComponent
        })
        .then((res: any) => {
            cb(null, res.code)
        })
        .catch((err: any) => {
            cb(err)
        })

    return
}

async transform(src, id) {
            // Filter user-land config and lwc import
            if (!filter(id)) {
                return;
            }

            // If we don't find the moduleId, just resolve the module name/namespace
            const moduleEntry = Object.values(modulePaths).find(r => id === r.entry);
            const moduleRegistry = moduleEntry || getModuleQualifiedName(id, mergedPluginOptions);

            const { code, map } = await compiler.transform(src, id, {
                mode: DEFAULT_MODE, // Use always default mode since any other (prod or compat) will be resolved later
                name: moduleRegistry.moduleName,
                namespace: moduleRegistry.moduleNamespace,
                moduleSpecifier: moduleRegistry.moduleSpecifier,
                outputConfig: { sourcemap: mergedPluginOptions.sourcemap },
                stylesheetConfig: mergedPluginOptions.stylesheetConfig,
                experimentalDynamicComponent: mergedPluginOptions.experimentalDynamicComponent,
            });

            return { code, map };
        },
    };

process(src, filePath) {
        // Set default module name and namespace value for the namespace because it can't be properly guessed from the path
        const { code, map } = lwcCompiler.transformSync(src, filePath, {
            moduleName: 'test',
            moduleNamespace: 'x',
            outputConfig: {
                sourcemap: true,
            },
        });

        // if is not .js, we add the .compiled extension in the sourcemap
        const filename = path.extname(filePath) === '.js' ? filePath : filePath + '.compiled';
        // **Note: .html and .css don't return valid sourcemaps cause they are used for rollup
        const config = map && map.version ? { inputSourceMap: map } : {};

        return babelCore.transform(code, { ...BABEL_CONFIG, ...config, filename });
    },
    getCacheKey(fileData, filePath, configStr, options) {

* All rights reserved.
 * SPDX-License-Identifier: MIT
 * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
 */
const path = require('path');
const crypto = require('crypto');
const { getVersion } = require('lwc');

const babelCore = require('@babel/core');
const lwcCompiler = require('@lwc/compiler');
const jestPreset = require('babel-preset-jest');
const babelCommonJs = require('@babel/plugin-transform-modules-commonjs');
const babelDynamicImport = require('babel-plugin-transform-dynamic-import');

const engineVersion = getVersion();
const compilerVersion = require('@lwc/compiler/package.json').version;

const apexScopedImport = require('./transforms/apex-scoped-import');
const apexContinuationScopedImport = require('./transforms/apex-continuation-scoped-import');
const customPermissionImport = require('./transforms/custom-permission-scoped-import');
const i18nScopedImport = require('./transforms/i18n-scoped-import');
const labelScopedImport = require('./transforms/label-scoped-import');
const resourceScopedImport = require('./transforms/resource-scoped-import');
const contentAssetUrlScopedImport = require('./transforms/content-asset-url-scoped-import');
const schemaScopedImport = require('./transforms/schema-scoped-import');
const userScopedImport = require('./transforms/user-scoped-import');
const userPermissionImport = require('./transforms/user-permission-scoped-import');
const clientScopedImport = require('./transforms/client-scoped-import');
const messageChannelScopedImport = require('./transforms/message-channel-scoped-import');

const BABEL_CONFIG = {
    sourceMaps: 'both',

export async function compileSource(source: string, fileName: string = 'foo.js'): Promise {
    try {
        const name = fileName.substring(0, fileName.lastIndexOf('.'));
        const options: CompilerOptions = {
            name,
            namespace: 'x',
            files: {},
        };
        const transformerResult = await transform(source, fileName, options);
        const metadata = transformerResult.metadata as Metadata;
        patchComments(metadata);
        return { metadata, diagnostics: [] };
    } catch (err) {
        return { diagnostics: [toDiagnostic(err)] };
    }
}

/*
 * Copyright (c) 2018, salesforce.com, inc.
 * All rights reserved.
 * SPDX-License-Identifier: MIT
 * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
 */
const path = require('path');
const crypto = require('crypto');

const babelCore = require('@babel/core');
const lwcCompiler = require('@lwc/compiler');
const jestPreset = require('babel-preset-jest');
const babelCommonJs = require('@babel/plugin-transform-modules-commonjs');

const engineVersion = require('@lwc/engine/package.json').version;
const compilerVersion = require('@lwc/compiler/package.json').version;

const apexScopedImport = require('./transforms/apex-scoped-import');
const apexContinuationScopedImport = require('./transforms/apex-continuation-scoped-import');
const i18nScopedImport = require('./transforms/i18n-scoped-import');
const labelScopedImport = require('./transforms/label-scoped-import');
const resourceScopedImport = require('./transforms/resource-scoped-import');
const contentAssetUrlScopedImport = require('./transforms/content-asset-url-scoped-import');
const schemaScopedImport = require('./transforms/schema-scoped-import');
const userScopedImport = require('./transforms/user-scoped-import');
const clientScopedImport = require('./transforms/client-scoped-import');

const BABEL_CONFIG = {
    sourceMaps: 'both',
    presets: [jestPreset],
    plugins: [
        babelCommonJs,