allow to unshift hooks

packages/commons/src/hooks.ts

@@ -73,6 +73,8 @@ export function convertHookData (obj: any) {
 
   if (Array.isArray(obj)) {
     hook = { all: obj };
+  } else if (obj.$unshift || obj.$push) {
+    hook = { all: obj };
   } else if (typeof obj !== 'object') {
     hook = { all: [ obj ] };
   } else {
@@ -139,6 +141,31 @@ export function processHooks (hooks: any[], initialHookObject: any) {
   });
 }
 
+function registerHooks (myHooks: any, hooks: any): any {
+  const hooksToRegister = Array.isArray(hooks) ? hooks : [hooks];
+
+  hooksToRegister.forEach(hook => {
+    if (typeof hook === 'function') {
+      myHooks.push(hook);
+    } else {
+      if (hook.$push) {
+        if (Array.isArray(hook.$push)) {
+          myHooks.push.apply(myHooks, hook.$push);
+        } else {
+          myHooks.push(hook.$push);
+        }
+      }
+      if (hook.$unshift) {
+        if (Array.isArray(hook.$unshift)) {
+          myHooks.unshift.apply(myHooks, hook.$unshift);
+        } else {
+          myHooks.unshift(hook.$unshift);
+        }
+      }
+    }
+  });
+}
+
 // Add `.hooks` functionality to an object
 export function enableHooks (obj: any, methods: string[], types: string[]) {
   if (typeof obj.hooks === 'function') {
@@ -180,11 +207,11 @@ export function enableHooks (obj: any, methods: string[], types: string[]) {
           const myHooks = this.__hooks[type][method] || (this.__hooks[type][method] = []);
 
           if (hooks.all) {
-            myHooks.push.apply(myHooks, hooks.all);
+            registerHooks(myHooks, hooks.all);
           }
 
           if (hooks[method]) {
-            myHooks.push.apply(myHooks, hooks[method]);
+            registerHooks(myHooks, hooks[method]);
           }
         });
       });

packages/commons/test/hooks.test.ts

@@ -350,6 +350,22 @@ describe('hook utilities', () => {
         expect(base.__hooks.dummy.testMethod).to.deep.equal([ fn ]);
       });
 
+      it('unshifts hook with custom type and `all` method', () => {
+        expect(typeof base.hooks).to.equal('function');
+
+        const fn = function () {};
+        const fn2 = function () {};
+        const fn3 = function () {};
+
+        base.hooks({ dummy: [fn] });
+        base.hooks({ dummy: {
+          all: { $unshift: [fn2] }
+        } });
+        base.hooks({ dummy: { $unshift: [fn3] } });
+
+        expect(base.__hooks.dummy.testMethod).to.deep.equal([ fn3, fn2, fn ]);
+      });
+
       it('registers hook with custom type and specific method', () => {
         base.hooks({
           dummy: {