feat: optional timeout (#200)

lib/circuit.js

@@ -30,7 +30,8 @@ Please use options.errorThresholdPercentage`;
  * There are **no default options** when you use the constructor directly. You
  * must supply values for each of these.
  * @param options.timeout {Number} The time in milliseconds that action should
- * be allowed to execute before timing out.
+ * be allowed to execute before timing out. Timeout can be disabled by setting
+ * this to `false`.
  * @param options.maxFailures {Number} The number of times the circuit can fail
  * before opening.
  * (deprecated - see {CircuitBreaker#options.errorThresholdPercentage})
@@ -315,23 +316,25 @@ class CircuitBreaker extends EventEmitter {
     return new Promise((resolve, reject) => {
       const latencyStartTime = Date.now();
       if (this.semaphore.test()) {
-        timeout = setTimeout(
-          () => {
-            timeoutError = true;
-            const error =
-              new Error(`Timed out after ${this.options.timeout}ms`);
-            error.code = 'ETIMEDOUT';
-            /**
-             * Emitted when the circuit breaker action takes longer than
-             * `options.timeout`
-             * @event CircuitBreaker#timeout
-             */
-            const latency = Date.now() - latencyStartTime;
-            this.semaphore.release();
-            this.emit('timeout', error, latency);
-            resolve(handleError(
-              error, this, timeout, args, latency, resolve, reject));
-          }, this.options.timeout);
+        if (this.options.timeout) {
+          timeout = setTimeout(
+            () => {
+              timeoutError = true;
+              const error =
+                new Error(`Timed out after ${this.options.timeout}ms`);
+              error.code = 'ETIMEDOUT';
+              /**
+               * Emitted when the circuit breaker action takes longer than
+               * `options.timeout`
+               * @event CircuitBreaker#timeout
+               */
+              const latency = Date.now() - latencyStartTime;
+              this.semaphore.release();
+              this.emit('timeout', error, latency);
+              resolve(handleError(
+                error, this, timeout, args, latency, resolve, reject));
+            }, this.options.timeout);
+        }
 
         try {
           const result = this.action.apply(this.action, args);