chore: Expose interceptorModule from WorkflowCoverage (#821)

Author: bergundy

packages/nyc-test-coverage/README.md

@@ -20,7 +20,7 @@ worker = await Worker.create({
   taskQueue,
   workflowsPath: require.resolve("./workflows"),
   interceptors: {
-    workflowModules: [require.resolve("@temporalio/nyc-test-coverage/lib/interceptors")]
+    workflowModules: [workflowCoverage.interceptorModule]
   },
   sinks: workflowCoverage.sinks,
 });
@@ -41,4 +41,4 @@ The following assumes that `npm run build` produces compiled JavaScript in the `
 {
   "test.coverage": "npm run build && nyc instrument lib lib --in-place && nyc --reporter=lcov --reporter=text-summary mocha lib/*.test.js"
 }
-```
+```

packages/nyc-test-coverage/src/index.ts

@@ -5,6 +5,13 @@ import libCoverage from 'istanbul-lib-coverage';
 export class WorkflowCoverage {
   coverageMap = libCoverage.createCoverageMap();
 
+  /**
+   * Interceptor to inject into `WorkerOptions.interceptors.workflowModules`
+   */
+  public get interceptorModule(): string {
+    return require.resolve('./interceptors');
+  }
+
   /**
    * Contains sinks that allow Workflows to gather coverage data.
    */

packages/nyc-test-coverage/src/interceptors.ts

@@ -1,6 +1,6 @@
 import { proxySinks, WorkflowInterceptors } from '@temporalio/workflow';
 import { CoverageSinks } from './sinks';
-import libCoverage from 'istanbul-lib-coverage';
+import type { CoverageMapData } from 'istanbul-lib-coverage';
 
 const { coverage } = proxySinks<CoverageSinks>();
 
@@ -11,7 +11,7 @@ export const interceptors = (): WorkflowInterceptors => ({
       concludeActivation(input, next) {
         /* eslint-disable @typescript-eslint/ban-ts-comment */
         // @ts-ignore
-        const globalCoverage: libCoverage.CoverageMapData = global.__coverage__;
+        const globalCoverage: CoverageMapData = global.__coverage__;
 
         coverage.merge(JSON.parse(JSON.stringify(globalCoverage)));
         clearCoverage(globalCoverage);
@@ -22,7 +22,7 @@ export const interceptors = (): WorkflowInterceptors => ({
   ],
 });
 
-function clearCoverage(coverage: libCoverage.CoverageMapData): void {
+function clearCoverage(coverage: CoverageMapData): void {
   for (const path of Object.keys(coverage)) {
     for (const index of Object.keys(coverage[path].s)) {
       coverage[path].s[index] = 0;