chore(gatsby): Convert utils/tracer/index to typescript (#22296)

* chore(gatsby): Convert utils/tracer/index to typescript

* Fix to individual import.

packages/gatsby/src/commands/build.js

@@ -8,7 +8,7 @@ import { buildProductionBundle } from "./build-javascript"
 const bootstrap = require(`../bootstrap`)
 const apiRunnerNode = require(`../utils/api-runner-node`)
 const { copyStaticDirs } = require(`../utils/get-static-dir`)
-const { initTracer, stopTracer } = require(`../utils/tracer`)
+import { initTracer, stopTracer } from "../utils/tracer"
 const db = require(`../db`)
 const signalExit = require(`signal-exit`)
 const telemetry = require(`gatsby-telemetry`)

packages/gatsby/src/utils/tracer/index.js → packages/gatsby/src/utils/tracer/index.ts

@@ -1,6 +1,6 @@
-const { slash } = require(`gatsby-core-utils`)
-const path = require(`path`)
-const opentracing = require(`opentracing`)
+import { slash } from "gatsby-core-utils"
+import path from "path"
+import { Tracer, initGlobalTracer } from "opentracing"
 
 let tracerProvider
 
@@ -13,28 +13,23 @@ let tracerProvider
  * `stop` - Run any tracer cleanup required before the node.js process
  * exits
  */
-function initTracer(tracerFile) {
-  let tracer
+export const initTracer = (tracerFile: string): Tracer => {
+  let tracer: Tracer
   if (tracerFile) {
     const resolvedPath = slash(path.resolve(tracerFile))
     tracerProvider = require(resolvedPath)
     tracer = tracerProvider.create()
   } else {
-    tracer = new opentracing.Tracer() // Noop
+    tracer = new Tracer() // Noop
   }
 
-  opentracing.initGlobalTracer(tracer)
+  initGlobalTracer(tracer)
 
   return tracer
 }
 
-async function stopTracer() {
+export const stopTracer = async (): Promise<void> => {
   if (tracerProvider && tracerProvider.stop) {
     await tracerProvider.stop()
   }
 }
-
-module.exports = {
-  initTracer,
-  stopTracer,
-}