feat: Scaffold browser client. (#579)

This adds a basic client and initialization function. The SDK does
function, but does not yet function like a JS SDK, but more like a
mobile SDK.

packages/sdk/browser/src/BrowserClient.ts

@@ -0,0 +1,43 @@
+import {
+  AutoEnvAttributes,
+  base64UrlEncode,
+  LDClient as CommonClient,
+  LDClientImpl,
+  LDContext,
+  LDOptions,
+} from '@launchdarkly/js-client-sdk-common';
+
+import BrowserPlatform from './platform/BrowserPlatform';
+
+/**
+ * We are not supporting dynamically setting the connection mode on the LDClient.
+ */
+export type LDClient = Omit<CommonClient, 'setConnectionMode'>;
+
+export class BrowserClient extends LDClientImpl {
+  constructor(
+    private readonly clientSideId: string,
+    autoEnvAttributes: AutoEnvAttributes,
+    options: LDOptions = {},
+  ) {
+    super(clientSideId, autoEnvAttributes, new BrowserPlatform(options), options, {
+      analyticsEventPath: `/events/bulk/${clientSideId}`,
+      diagnosticEventPath: `/events/diagnostic/${clientSideId}`,
+      includeAuthorizationHeader: false,
+      highTimeoutThreshold: 5,
+      userAgentHeaderName: 'x-launchdarkly-user-agent',
+    });
+  }
+
+  private encodeContext(context: LDContext) {
+    return base64UrlEncode(JSON.stringify(context), this.platform.encoding!);
+  }
+
+  override createStreamUriPath(context: LDContext) {
+    return `/eval/${this.clientSideId}/${this.encodeContext(context)}`;
+  }
+
+  override createPollUriPath(context: LDContext): string {
+    return `/sdk/evalx/${this.clientSideId}/contexts/${this.encodeContext(context)}`;
+  }
+}

packages/sdk/browser/src/index.ts

@@ -1,11 +1,37 @@
-import BrowserInfo from './platform/BrowserInfo';
-import DefaultBrowserEventSource from './platform/DefaultBrowserEventSource';
+import {
+  AutoEnvAttributes,
+  LDContext,
+  LDContextCommon,
+  LDContextMeta,
+  LDFlagSet,
+  LDLogger,
+  LDLogLevel,
+  LDMultiKindContext,
+  LDOptions,
+  LDSingleKindContext,
+} from '@launchdarkly/js-client-sdk-common';
 
-// Temporary exports for testing in a browser.
-export { DefaultBrowserEventSource, BrowserInfo };
-export * from '@launchdarkly/js-client-sdk-common';
+import { BrowserClient, LDClient } from './BrowserClient';
 
-export function Hello() {
-  // eslint-disable-next-line no-console
-  console.log('HELLO');
+// TODO: Export and use browser specific options.
+export {
+  LDClient,
+  AutoEnvAttributes,
+  LDOptions,
+  LDFlagSet,
+  LDContext,
+  LDContextCommon,
+  LDContextMeta,
+  LDMultiKindContext,
+  LDSingleKindContext,
+  LDLogLevel,
+  LDLogger,
+};
+
+export function init(
+  clientSideId: string,
+  autoEnvAttributes: AutoEnvAttributes,
+  options?: LDOptions,
+): LDClient {
+  return new BrowserClient(clientSideId, autoEnvAttributes, options);
 }