FlagshipFlag

Source: src/Cloudflare/Flagship/Flag.ts

A feature flag in a Cloudflare Flagship app.

A flag maps a key to a set of variations plus targeting rules. Workers evaluate flags through the Flagship binding (or the REST evaluate endpoint); changing variations, rules, enablement, or the default variation takes effect without redeploying code. Everything except the flag key and the parent app is mutable in place.

Creating a Flag

Boolean flag

const app = yield* Cloudflare.FlagshipApp("Flags", {});

const flag = yield* Cloudflare.FlagshipFlag("NewCheckout", {
  appId: app.appId,
  key: "new-checkout",
  defaultVariation: "off",
  variations: { off: false, on: true },
});

String flag with multiple variations

const flag = yield* Cloudflare.FlagshipFlag("CheckoutFlow", {
  appId: app.appId,
  key: "checkout-flow",
  defaultVariation: "v1",
  variations: { v1: "classic", v2: "express", v3: "one-click" },
});

Targeting Rules

Serve a variation to a specific country

const flag = yield* Cloudflare.FlagshipFlag("DarkMode", {
  appId: app.appId,
  key: "dark-mode",
  defaultVariation: "off",
  variations: { off: false, on: true },
  rules: [
    {
      priority: 1,
      conditions: [
        { attribute: "country", operator: "equals", value: "US" },
      ],
      serveVariation: "on",
    },
  ],
});

Percentage rollout

const flag = yield* Cloudflare.FlagshipFlag("NewSearch", {
  appId: app.appId,
  key: "new-search",
  defaultVariation: "off",
  variations: { off: false, on: true },
  rules: [
    {
      priority: 1,
      conditions: [],
      serveVariation: "on",
      rollout: { percentage: 25 },
    },
  ],
});

Toggling a Flag

const flag = yield* Cloudflare.FlagshipFlag("NewCheckout", {
  appId: app.appId,
  key: "new-checkout",
  enabled: false,
  defaultVariation: "off",
  variations: { off: false, on: true },
});