fix(cli): extract migrate as a separate command

src/cli.ts

@@ -6,7 +6,7 @@ import {
 } from './utils';
 import { sassBuild, sassBuildFiles, sassBuildString } from './build';
 import { sassCompile } from './compile';
-import { migrateCompilerConfig } from './config-migrate';
+import { migrate } from './migrate';
 import { buildConfig } from './config-build';
 
 const commandMap = {
@@ -231,12 +231,12 @@ function cli_compile(params) {
 
 // eslint-disable-next-line camelcase
 function cli_migrate(params) {
-    const { file, outFile } = params;
+    const { file, outFile, transformer } = params;
 
     const src = file || COMPILER_CONFIG;
     const dest = outFile || SASS_CONFIG;
 
-    migrateCompilerConfig( src, dest );
+    migrate( src, dest, transformer );
 }
 
 

src/config-migrate.ts → src/migrate/complier-config-transformer.ts

@@ -1,12 +1,11 @@
+import fs from 'fs';
+
 import {
     exit,
-    logger,
-    requireUserFile,
-    fileExists,
-    writeFile
-} from './utils';
+    fileExists
+} from '../utils';
 
-type CompilerConfigFileEntry = {
+type CompilerConfigEntry = {
     inputFile: string;
     outputFile: string;
     minify: {
@@ -18,24 +17,21 @@ type CompilerConfigFileEntry = {
     }
 }
 
-export function migrateCompilerConfig(src : string, dest : string) {
-
-    if (!fileExists(src)) {
-        exit(2, 'error', 'migrate', `Cannot find file ${src}`);
+export function compilerConfigTransformer(pathToConfig: string) {
+    if (!fileExists(pathToConfig)) {
+        exit(2, 'error', 'migrate > transformer', `Cannot find file ${pathToConfig}`);
     }
 
-    logger.silly('migrate', 'Found %s.', src);
-    logger.silly('migrate', '  Migrating...');
+    const compilerConfigJson : CompilerConfigEntry[] = JSON.parse(fs.readFileSync( pathToConfig, 'utf-8' ));
 
-    const compilerConfigContent : CompilerConfigFileEntry[] = requireUserFile(src);
     let sassConfigContent : any = {
         extends: [
             'sass-build:recommended'
         ],
         files: []
     };
 
-    compilerConfigContent.forEach(oldEntry => {
+    compilerConfigJson.forEach(oldEntry => {
         const newEntry = {
             file: oldEntry.inputFile,
             outFile: oldEntry.outputFile,
@@ -52,8 +48,5 @@ export function migrateCompilerConfig(src : string, dest : string) {
         return space + word.replaceAll('"', '');
     });
 
-    writeFile( dest, sassConfigContent );
-
-    logger.info('migrate', 'Successfully migrated %s to %s', src, dest );
-
+    return sassConfigContent;
 }

src/migrate/index.ts

@@ -0,0 +1 @@
+export * from './migrate';

src/migrate/migrate.ts

@@ -0,0 +1,37 @@
+import {
+    exit,
+    logger,
+    requireUserFile,
+    fileExists,
+    writeFile
+} from '../utils';
+import { compilerConfigTransformer } from './complier-config-transformer';
+
+
+export function migrate(src: string, dest: string, transformer: string | Function = compilerConfigTransformer) {
+
+    if (!fileExists(src)) {
+        exit(2, 'error', 'migrate', `Cannot find file ${src}`);
+    }
+
+    if (typeof transformer === 'string') {
+        if (!fileExists(transformer)) {
+            exit(2, 'error', 'migrate', `Cannot find file ${src}`);
+        }
+        // eslint-disable-next-line no-param-reassign
+        transformer = <Function> requireUserFile(transformer);
+    }
+
+    if (typeof transformer !== 'function') {
+        exit(22, 'error', 'migrate', `Transformer is not a function.`);
+    }
+
+    logger.silly('migrate', 'Found %s.', src);
+    logger.silly('migrate', '  Migrating...');
+
+    const sassConfigContent = transformer( src );
+
+    writeFile( dest, sassConfigContent );
+
+    logger.info('migrate', 'Successfully migrated %s to %s', src, dest );
+}