feat: Vendor TraceKit (launchdarkly#729)

This PR vendors tracekit to alleviate some issues with ESM
compatibility.
Currently the typescript conversion is minimal. It adds the types which
are largely compatible and leaves most of it reasonably unchanged.

This PR does not port the tests from tracekit to this repository. A
subsequent PR will do this.

BEGIN_COMMIT_OVERRIDE
feat: Vendor TraceKit
feat: Export browser-telemetry initialization method.
END_COMMIT_OVERRIDE

Jira: EMSR-14
Jira: EMSR-15

Author: kinyoklion

packages/telemetry/browser-telemetry/package.json

@@ -43,9 +43,6 @@
   "bugs": {
     "url": "https://github.com/launchdarkly/js-core/issues"
   },
-  "dependencies": {
-    "tracekit": "^0.4.6"
-  },
   "devDependencies": {
     "@jest/globals": "^29.7.0",
     "@launchdarkly/js-client-sdk": "0.3.2",

packages/telemetry/browser-telemetry/src/BrowserTelemetryImpl.ts

@@ -1,5 +1,3 @@
-import * as TraceKit from 'tracekit';
-
 /**
  * A limited selection of type information is provided by the browser client SDK.
  * This is only a type dependency and these types should be compatible between
@@ -23,6 +21,7 @@ import makeInspectors from './inspectors';
 import { ParsedOptions, ParsedStackOptions } from './options';
 import randomUuidV4 from './randomUuidV4';
 import parse from './stack/StackParser';
+import { getTraceKit } from './vendor/TraceKit';
 
 // TODO: Use a ring buffer for the breadcrumbs/pending events instead of shifting. (SDK-914)
 
@@ -54,13 +53,18 @@ function safeValue(u: unknown): string | boolean | number | undefined {
 }
 
 function configureTraceKit(options: ParsedStackOptions) {
+  const TraceKit = getTraceKit();
   // Include before + after + source line.
   // TraceKit only takes a total context size, so we have to over capture and then reduce the lines.
   // So, for instance if before is 3 and after is 4 we need to capture 4 and 4 and then drop a line
   // from the before context.
   // The typing for this is a bool, but it accepts a number.
   const beforeAfterMax = Math.max(options.source.afterLines, options.source.beforeLines);
-  (TraceKit as any).linesOfContext = beforeAfterMax * 2 + 1;
+  // The assignment here has bene split to prevent esbuild from complaining about an assigment to
+  // an import. TraceKit exports a single object and the interface requires modifying an exported
+  // var.
+  const anyObj = TraceKit as any;
+  anyObj.linesOfContext = beforeAfterMax * 2 + 1;
 }
 
 export default class BrowserTelemetryImpl implements BrowserTelemetry {

packages/telemetry/browser-telemetry/src/index.ts

@@ -1 +1,11 @@
+import { BrowserTelemetry } from './api/BrowserTelemetry';
+import { Options } from './api/Options';
+import BrowserTelemetryImpl from './BrowserTelemetryImpl';
+import parse from './options';
+
 export * from './api';
+
+export function initializeTelemetry(options?: Options): BrowserTelemetry {
+  const parsedOptions = parse(options || {});
+  return new BrowserTelemetryImpl(parsedOptions);
+}

packages/telemetry/browser-telemetry/src/stack/StackParser.ts

@@ -1,8 +1,7 @@
-import { computeStackTrace } from 'tracekit';
-
 import { StackFrame } from '../api/stack/StackFrame';
 import { StackTrace } from '../api/stack/StackTrace';
 import { ParsedStackOptions } from '../options';
+import { getTraceKit } from '../vendor/TraceKit';
 
 /**
  * In the browser we will not always be able to determine the source file that code originates
@@ -195,7 +194,7 @@ export function getSrcLines(
  * @returns The stack trace for the given error.
  */
 export default function parse(error: Error, options: ParsedStackOptions): StackTrace {
-  const parsed = computeStackTrace(error);
+  const parsed = getTraceKit().computeStackTrace(error);
   const frames: StackFrame[] = parsed.stack.reverse().map((inFrame) => ({
     fileName: processUrlToFileName(inFrame.url, window.location.origin),
     function: inFrame.func,