fix(typescript): replace runtime undefined with void 0 in new code\n\n- watchProgram: use void 0 when resetting cached transformers in watch mode\n- tests: use void 0 in new watch-mode transformer test to satisfy no-undefined\n\nRefs PR #1923 review feedback from @shellscape

Author: CharlieHelps

packages/typescript/src/watchProgram.ts

@@ -165,7 +165,7 @@ function createWatchHost(
       // Ensure we recompute custom transformers for each new builder program in watch mode
       // so factories capture the current Program/TypeChecker and any provided getters return
       // the latest values. This avoids freezing the initial Program across rebuilds.
-      createdTransformers = undefined;
+      createdTransformers = void 0;
       const origEmit = program.emit;
       // eslint-disable-next-line no-param-reassign
       program.emit = (

packages/typescript/test/test.js

@@ -1747,7 +1747,7 @@ test.serial(
                 factory(program, getProgram) {
                   observations.push({
                     p: program && program.id,
-                    gp: getProgram ? getProgram().id : undefined
+                    gp: getProgram ? getProgram().id : void 0
                   });
                   // no-op transformer
                   return function passthroughFactory(context) {