fix: require tscompiler on current process (#207)

let current command process can require ts files

lib/command.js

@@ -111,8 +111,23 @@ class Command extends BaseCommand {
     if (argv.typescript) {
       execArgvObj.require.push(argv.tscompiler);
 
+      // should require argv.tscompiler on current process, let it can require *.ts files
+      // e.g.: dev command will execute egg loader to find configs and plugins
+      require(argv.tscompiler);
+      // let child process auto require ts-node too
+      const requireOptions = `--require ${argv.tscompiler}`;
+      if (process.env.NODE_OPTIONS) {
+        if (!process.env.NODE_OPTIONS.includes(requireOptions)) {
+          process.env.NODE_OPTIONS = `${process.env.NODE_OPTIONS} ${requireOptions}`;
+        }
+      } else {
+        process.env.NODE_OPTIONS = requireOptions;
+      }
       // tell egg loader to load ts file
+      // see https://github.com/eggjs/egg-core/blob/master/lib/loader/egg_loader.js#L443
       env.EGG_TYPESCRIPT = 'true';
+      // set current process.env.EGG_TYPESCRIPT too
+      process.env.EGG_TYPESCRIPT = 'true';
 
       // load files from tsconfig on startup
       env.TS_NODE_FILES = process.env.TS_NODE_FILES || 'true';