flagr-feature-typescript

Prerequisites

To use this package, you will need to have Flagr installed and accessible

Usage

Configuration

const feature = createFeature({ flagrUrl: 'http://localhost:18000' });

Evaluation

const evaluation = feature.evaluate('flag', {
  on: (attachment) => true, // do stuff when feature is on,
  otherwise: (attachment) => false, // do stuff when any other variant isn't matched
});
console.log(evaluation); // return from evaluate

Conditional

const match = feature.match('flag'); // true if evaluated variant is 'on'
const matchOff = feature.match('flag2', 'off'); // true evaluated variant is 'off'

Synchronous usage

In the event that you can't use promises (such as within React components), you can directly use the evaluator.

// Invoked in a global context
const evaluator = createEvaluator(config);
const { cachedMatch, cachedEvaluation } = await evaluator.batchEvaluation({
  id: 'user_123',
  context: {}
  input: {
    tags: ['local'],
  },
});

// ...
// Invoked in a synchronous context
const isOn = cachedMatch('flag1');

NB: All flags are prefetched via the evaluator. This requires you to supply the superset flags required via either keys or tags

Context

Context can be sent during evaluation

feature.setContext({
  env: 'production',
  user: { id: 1, username: 'user' },
});