strict check current to equla to target, or throw exception

src/state-monitor.spec.ts

@@ -63,3 +63,13 @@ test('StateMonitor client & stable/inprocess', t => {
   t.true(sm.stable(), 'should be stable')
   t.false(sm.inprocess(), 'should be not inprocess')
 })
+
+test('current() strict check with target', t => {
+  const CLIENT_NAME = 'StateMonitorTest'
+  const sm = new StateMonitor<'A', 'B'>(CLIENT_NAME, 'A')
+
+  t.throws(() => sm.current('B'), Error, 'should thorw for unmatch current & target')
+
+  sm.target('B')
+  t.notThrows(() => sm.current('B'), 'should not throws for matched current & target')
+})

src/state-monitor.ts

@@ -58,6 +58,20 @@ export class StateMonitor <A, B>{
                                 , this._current, this._stable
                 )
 
+      /**
+       * strict check current is equal to target
+       */
+      if (this._target !== newState) {
+        log.warn('StateMonitor', '%s:current(%s,%s) current is different with target. call state.target(%s) first.'
+                                , this._client
+                                , newState, stable
+                                , newState
+        )
+        const e = new Error('current not match target')
+        log.verbose('StateMonitor', e.stack)
+        throw e
+      }
+
       /**
        * warn for inprocess current state change twice, mostly like a logic bug outside
        */