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1 | 1 | import * as LaunchDarkly from '@launchdarkly/node-server-sdk';
|
2 | 2 |
|
3 | 3 | // Set sdkKey to your LaunchDarkly SDK key.
|
4 |
| -const sdkKey = ""; |
| 4 | +const sdkKey = process.env.LAUNCHDARKLY_SDK_KEY ?? 'your-sdk-key'; |
5 | 5 |
|
6 | 6 | // Set featureFlagKey to the feature flag key you want to evaluate.
|
7 |
| -const featureFlagKey = "my-boolean-flag"; |
| 7 | +const featureFlagKey = process.env.LAUNCHDARKLY_FLAG_KEY ?? 'sample-feature'; |
8 | 8 |
|
9 |
| -// Set up the context properties. This use should appear on your LaunchDarkly |
10 |
| -// contexts dashboard soon after you run the demo. |
| 9 | +function showBanner() { |
| 10 | + console.log( |
| 11 | + ` ██ |
| 12 | + ██ |
| 13 | + ████████ |
| 14 | + ███████ |
| 15 | +██ LAUNCHDARKLY █ |
| 16 | + ███████ |
| 17 | + ████████ |
| 18 | + ██ |
| 19 | + ██ |
| 20 | +`, |
| 21 | + ); |
| 22 | +} |
| 23 | + |
| 24 | +function printValueAndBanner(flagValue: boolean) { |
| 25 | + console.log(`*** The '${featureFlagKey}' feature flag evaluates to ${flagValue}.`); |
| 26 | + |
| 27 | + if (flagValue) showBanner(); |
| 28 | +} |
| 29 | + |
| 30 | +if (!sdkKey) { |
| 31 | + console.log('*** Please edit index.js to set sdkKey to your LaunchDarkly SDK key first.'); |
| 32 | + process.exit(1); |
| 33 | +} |
| 34 | + |
| 35 | + |
| 36 | +const ldClient = LaunchDarkly.init(sdkKey); |
| 37 | + |
| 38 | +// Set up the context properties. This context should appear on your LaunchDarkly contexts dashboard |
| 39 | +// soon after you run the demo. |
11 | 40 | const context = {
|
12 |
| - "kind": "user", |
13 |
| - "name": "Sandy", |
14 |
| - "key": "example-context-key" |
| 41 | + kind: 'user', |
| 42 | + key: 'example-user-key', |
| 43 | + name: 'Sandy', |
15 | 44 | };
|
16 | 45 |
|
17 |
| -function showMessage(s: string) { |
18 |
| - console.log("*** " + s); |
19 |
| - console.log(""); |
20 |
| -} |
| 46 | +async function main() { |
| 47 | + try { |
| 48 | + await ldClient.waitForInitialization({timeout: 10}); |
21 | 49 |
|
22 |
| -const client = LaunchDarkly.init(sdkKey); |
23 |
| - |
24 |
| -client.once('ready', function () { |
25 |
| - showMessage("SDK successfully initialized!"); |
26 |
| - client.variation(featureFlagKey, context, false, function (err, showFeature) { |
27 |
| - client.track("event-called", context); |
28 |
| - if (showFeature) { |
29 |
| - // application code to show the feature |
30 |
| - showMessage("Feature flag '" + featureFlagKey + "' is true for this context"); |
31 |
| - } else { |
32 |
| - // the code to run if the feature is off |
33 |
| - showMessage("Feature flag '" + featureFlagKey + "' is false for this context"); |
34 |
| - } |
| 50 | + console.log('*** SDK successfully initialized!'); |
35 | 51 |
|
36 |
| - // Here we ensure that the SDK shuts down cleanly and has a chance to deliver analytics |
37 |
| - // events to LaunchDarkly before the program exits. If analytics events are not delivered, |
38 |
| - // the context properties and flag usage statistics will not appear on your dashboard. In a |
39 |
| - // normal long-running application, the SDK would continue running and events would be |
40 |
| - // delivered automatically in the background. |
41 |
| - client.flush(function () { |
42 |
| - client.close(); |
| 52 | + const eventKey = `update:${featureFlagKey}`; |
| 53 | + ldClient.on(eventKey, async () => { |
| 54 | + const flagValue = await ldClient.variation(featureFlagKey, context, false); |
| 55 | + printValueAndBanner(flagValue); |
43 | 56 | });
|
44 |
| - }); |
45 |
| -}); |
| 57 | + |
| 58 | + const flagValue = await ldClient.variation(featureFlagKey, context, false); |
| 59 | + printValueAndBanner(flagValue); |
| 60 | + |
| 61 | + if (typeof process.env.CI !== "undefined") { |
| 62 | + process.exit(0); |
| 63 | + } |
| 64 | + } catch (error) { |
| 65 | + console.log(`*** SDK failed to initialize: ${error}`); |
| 66 | + process.exit(1); |
| 67 | + } |
| 68 | + |
| 69 | +} |
| 70 | + |
| 71 | +main(); |
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