timers-browserify

timers-browserify replaces Node.js’s built-in timers module for code bundled with browserify or compatible tools, so libraries written against Node’s timer internals keep working unmodified in the browser. Beyond the familiar setTimeout, clearTimeout, setInterval, and clearInterval, it reimplements the module’s private enroll, unenroll, and active/_unrefActive functions that other Node core modules rely on internally for idle-timeout bookkeeping, and polyfills setImmediate/clearImmediate via the separate setimmediate package.

The package is deliberately minimal — a single ~64-line file with one runtime dependency — and has been the default browserify substitute for the timers module since 2012. Its version history is almost entirely defensive maintenance, patching how it detects the correct global scope (window, self, or global) across newer bundlers and worker contexts as the JavaScript ecosystem’s build tooling diversified.

What You Get

• Drop-in browser replacements for Node’s setTimeout, setInterval, clearTimeout, and clearInterval.
• The private enroll, unenroll, and active timer-bookkeeping functions other Node modules depend on internally.
• A setImmediate/clearImmediate polyfill sourced from the setimmediate package.
• Automatic substitution when bundling with browserify, with no configuration required.

Common Use Cases

• Bundling a Node library that touches the internal timers API for browser delivery via browserify.
• Keeping legacy build pipelines working without rewriting every dependency’s timer usage.
• Polyfilling setImmediate/clearImmediate for code that assumes Node’s timer surface.
• Supporting web worker contexts where global scope detection differs from the main thread.

Under The Hood

Architecture timers-browserify ships as a single ~64-line CommonJS module (main.js) that acts as a thin delegation layer rather than a reimplementation: setTimeout/setInterval/clearTimeout/clearInterval wrap the native scope-detected timer functions (global, self, or window, whichever is present) and box the returned id in a small Timeout object exposing Node’s ref()/unref()/close() surface; enroll, unenroll, and active/_unrefActive reimplement Node’s private idle-timeout bookkeeping (setting _idleTimeout, clearing and rescheduling via the wrapped setTimeout) so code written against Node’s internal timers API keeps working unmodified when bundled for the browser; setImmediate/clearImmediate are sourced by requiring the separate setimmediate package and then probed across self, global, and this to find wherever that polyfill attached itself. There’s no internal layering, dependency injection, or state beyond the closure-scoped scope variable — the entire “architecture” is scope detection plus API-shape mimicry, appropriate for a module whose only job is bridging one bundler’s expectations to whatever host environment it lands in.

Tech Stack The package has exactly one runtime dependency, setimmediate (^1.0.4), used solely to polyfill setImmediate/clearImmediate; browserify (~1.10.16) and connect (~2.30.2) are devDependencies wired only into the example/enroll demo (a tiny connect+browserify static server, not part of the published module). There is no build step — main.js is published as-is — no bundler config, and no TypeScript; the package.json also carries a jspm map entry aliasing the module to Node’s built-in @node/timers for JSPM-based bundlers, showing its role is purely infrastructural glue for whichever bundler resolves the timers import.

Code Quality No test files, test framework, or test script exist anywhere in the repository — package.json defines no test command and there’s no tests/ or spec/ directory, so the module’s correctness is verified only by downstream bundler ecosystems consuming it at scale. Error handling is minimal by design (the module simply proxies to native timer functions, guarding only against a null timeout in clearTimeout/clearInterval), naming closely mirrors Node’s own timers API, and there is no type safety, linter config, or CI workflow (no .github/workflows directory) checked into the repo — quality assurance here has historically come from its role as a transitive browserify default, not from in-repo verification.

API Design The module’s entire design goal is zero-friction drop-in compatibility: every export (setTimeout, clearInterval, enroll, active, setImmediate, etc.) matches Node’s timers module name-for-name, so consuming code requires no adaptation and bundlers like browserify substitute it automatically without any configuration from the end developer. The tradeoff is that this mimicry is also the whole API surface — there’s no additional convenience layer, and the CHANGELOG shows the project’s history is almost entirely defensive: patching how scope/self/global are probed across different bundlers (Webpack, Browserify) and runtime contexts (workers) as they multiplied over the years, rather than adding new capability.