feature-release

A simple feature flag management without hassle

• Release by percentage
• Release by individual targets

How to use?

Simple usage by percentage release

1. Initialize feature flags

/* my-feature-release.js */
const { initFeatureRelease } = require('feature-release');
// or import { initFeatureRelease } from 'feature-release';

const featureRelease = initFeatureRelease({
  myFirstFeatureFlag: {
    releaseByPercentage: 30,
  },
  mySecondFeatureFlag: {
    releaseByPercentage: 100,
  },
});

module.exports = {
  featureRelease,
};

2. Use the feature flags with unique IDs

const { featureRelease } = require('./my-feature-release');

function newFeatureImplementation1(userID) {
  // The same userID will return the same result consistently.
  // For example, if userID, '12345', started to return true at 30%, it will
  // return true all from 30% to 100%.
  if (featureRelease.isEnabled('myFirstFeatureFlag', userID)) {
    return 'Oh! 30% of users will see this message!';
  } else {
    return 'Oh! 70% of users will see this message!';
  }
}

function newFeatureImplementation2(userID) {
  if (featureRelease.isEnabled('mySecondFeatureFlag', userID)) {
    return 'Oh! all users will see this message!';
  } else {
    return 'Oh! No user will see this message because you released 100%!';
  }
}

Simple usage by individual targets

1. Initialize feature flags

/* my-feature-release.js */
const { initFeatureRelease } = require('feature-release');
// or import { initFeatureRelease } from 'feature-release';

const featureRelease = initFeatureRelease({
  myFirstFeatureFlag: {
    individualTargets: {
      10001: true,
      10002: true,
    },
  },
  mySecondFeatureFlag: {
    individualTargets: {
      '[email protected]': true,
      '[email protected]': true,
    },
  },
});

module.exports = {
  featureRelease,
};

2. Use the feature flags with unique IDs

const { featureRelease } = require('./my-feature-release');

function newFeatureImplementation1(userID) {
  if (featureRelease.isEnabled('myFirstFeatureFlag', userID)) {
    return 'Oh! the userID, 10001 and 10002, will see this message!';
  } else {
    return 'Oh! all other users see this message!';
  }
}

function newFeatureImplementation2(email) {
  if (featureRelease.isEnabled('mySecondFeatureFlag', email)) {
    return 'Oh! the emails, [email protected] and [email protected], will see this message!';
  } else {
    return 'Oh! all other users see this message!';
  }
}

Simple usage by both percentage and targets

1. Initialize feature flags

/* my-feature-release.js */
const { initFeatureRelease } = require('feature-release');
// or import { initFeatureRelease } from 'feature-release';

const featureRelease = initFeatureRelease({
  myFirstFeatureFlag: {
    releaseByPercentage: 30,
    individualTargets: {
      10001: true,
      10002: false,
    },
  },
  mySecondFeatureFlag: {
    individualTargets: {
      '[email protected]': false,
      '[email protected]': false,
    },
    releaseByPercentage: 100,
  },
});

module.exports = {
  featureRelease,
};

2. Use the feature flags with unique IDs

const { featureRelease } = require('./my-feature-release');

function newFeatureImplementation1(userID) {
  if (featureRelease.isEnabled('myFirstFeatureFlag', userID)) {
    return '1) the userID, 10001, will see this message. 2) 30% of users will see this message, too!';
  } else {
    return '1) the userID, 10002, will see this message. 2) 70% of users will see this message, too!';
  }
}

function newFeatureImplementation2(email) {
  if (featureRelease.isEnabled('mySecondFeatureFlag', email)) {
    return 'All users will see this message except [email protected] and [email protected]';
  } else {
    return '[email protected] and [email protected], will see this message even if it is released 100%';
  }
}

Advanced usage

Namespace

The namespace acts like an independent feature flag. However, it's convenient if you like to organize different subcategories under the same feature flag name.

1. Initialize feature flags

/* my-feature-release.js */
const { initFeatureRelease } = require('feature-release');
// or import { initFeatureRelease } from 'feature-release';

const featureRelease = initFeatureRelease({
  myFirstFeatureFlag: {
    'prod-west1': {
      releaseByPercentage: 30,
      individualTargets: {
        10001: true,
      },
    },
    'prod-east1': {
      releaseByPercentage: 40,
      individualTargets: {
        10002: true,
      },
    },
  },
});

module.exports = {
  featureRelease,
};

2. Use the feature flags with unique IDs and the namespace

const { featureRelease } = require('./my-feature-release');

function newFeatureImplementation1(userID, environment, region) {
  if (featureRelease.isEnabled('myFirstFeatureFlag', userID, `${environment}-${region}`)) {
    return 'Oh! 30% of users and userID(10001) in prod-west1 will see this message while 40% of users and userID(10002) in prod-east1 see this message';
  } else {
    return 'Oh! other users will see this message!';
  }
}

Remote configuration

You can also pull the configuration from a remote server. There is also an option that pulls the configuration periodically. In this way, you are able to change the configuration remotely without restarting your application.

// https://example.com/remote-config.json
{
  "myFirstFeatureFlag": {
    "individualTargets": {
      "10001": true,
      "10002": true
    }
  },
  "mySecondFeatureFlag": {
    "individualTargets": {
      "[email protected]": true,
      "[email protected]": true
    }
  }
}

/* my-feature-release.js */
const { initFeatureReleaseAsync } = require('feature-release');
// or import { initFeatureReleaseAsync } from 'feature-release';

let featureRelease = undefined;

async function getFeatureReleaseInstance() {
  if(!featureRelease) {
    featureRelease = await initFeatureReleaseAsync({
      hostedConfigUrl: 'https://example.com/remote-config.json',
      // enableConfigPolling: false, // Optional. Default to false. Pulls the configuration from the `hostedConfigUrl` every `pollingIntervalInSeconds` seconds.
      // pollingIntervalInSeconds: 60, // Optional. Default to 60 seconds.
    });
    return featureRelease;
  }

  return featureRelease;
}

module.exports = {
  getFeatureReleaseInstance,
};