types(vest): shared callback type

packages/shared/src/bus.ts

@@ -1,24 +1,32 @@
+import { CB } from 'utilityTypes';
+
 export function createBus(): {
-  on: (event: string, handler: (...args: any[]) => void) => { off: () => void };
+  on: (event: string, handler: CB) => OnReturn;
   emit: (event: string, ...args: any[]) => void;
 } {
-  const listeners: Record<string, ((...args: any[]) => void)[]> = {};
+  const listeners: Record<string, CB[]> = {};
 
   return {
     emit(event: string, data: any) {
-      (listeners[event] || []).forEach(handler => {
+      listener(event).forEach(handler => {
         handler(data);
       });
     },
 
-    on(event: string, handler: (...args: any[]) => void): { off: () => void } {
-      listeners[event] = (listeners[event] || []).concat(handler);
+    on(event: string, handler: CB): OnReturn {
+      listeners[event] = listener(event).concat(handler);
 
       return {
         off() {
-          listeners[event] = listeners[event].filter(h => h !== handler);
+          listeners[event] = listener(event).filter(h => h !== handler);
         },
       };
     },
   };
+
+  function listener(event: string): CB[] {
+    return listeners[event] || [];
+  }
 }
+
+type OnReturn = { off: () => void };

packages/shared/src/utilityTypes.ts

@@ -3,3 +3,5 @@ export type DropFirst<T extends unknown[]> = T extends [unknown, ...infer U]
   : never;
 
 export type TStringable = string | ((...args: any[]) => string);
+
+export type CB = (...args: any[]) => void;

packages/vest/src/core/ctx/ctx.ts

@@ -1,6 +1,7 @@
 import assign from 'assign';
 import { createContext } from 'context';
 import { createCursor } from 'cursor';
+import { CB } from 'utilityTypes';
 
 import { IsolateKeys, IsolateTypes } from 'IsolateTypes';
 import { Modes } from 'Modes';
@@ -52,7 +53,7 @@ type CTXType = {
   bus?: {
     on: (
       event: string,
-      handler: (...args: any[]) => void
+      handler: CB
     ) => {
       off: () => void;
     };

packages/vest/src/core/isolate/isolates/omitWhen.ts

@@ -1,4 +1,5 @@
 import optionalFunctionValue from 'optionalFunctionValue';
+import { CB } from 'utilityTypes';
 
 import { IsolateTypes } from 'IsolateTypes';
 import ctx from 'ctx';
@@ -16,7 +17,7 @@ import { produceSuiteResult, SuiteResult } from 'produceSuiteResult';
  */
 export default function omitWhen(
   conditional: boolean | ((draft: SuiteResult) => boolean),
-  callback: (...args: any[]) => void
+  callback: CB
 ): void {
   isolate({ type: IsolateTypes.OMIT_WHEN }, () => {
     ctx.run(

packages/vest/src/core/isolate/isolates/skipWhen.ts

@@ -1,4 +1,5 @@
 import optionalFunctionValue from 'optionalFunctionValue';
+import { CB } from 'utilityTypes';
 
 import { IsolateTypes } from 'IsolateTypes';
 import ctx from 'ctx';
@@ -16,7 +17,7 @@ import { produceSuiteResult, SuiteResult } from 'produceSuiteResult';
  */
 export default function skipWhen(
   conditional: boolean | ((draft: SuiteResult) => boolean),
-  callback: (...args: any[]) => void
+  callback: CB
 ): void {
   isolate({ type: IsolateTypes.SKIP_WHEN }, () => {
     ctx.run(

packages/vest/src/core/suite/create.ts

@@ -2,6 +2,7 @@ import assign from 'assign';
 import genId from 'genId';
 import invariant from 'invariant';
 import isFunction from 'isFunction';
+import { CB } from 'utilityTypes';
 import { createState } from 'vast';
 
 import { IsolateTypes } from 'IsolateTypes';
@@ -19,8 +20,6 @@ type CreateProperties = {
   remove: (fieldName: string) => void;
 };
 
-type CB = (...args: any[]) => void;
-
 export type Suite<T extends CB> = {
   (...args: Parameters<T>): SuiteRunResult;
 } & CreateProperties;