wrote code

index.js

@@ -0,0 +1,42 @@
+'use strict'
+function _callFunc(self, obj, args){
+    const fn = typeof obj === 'function' ? obj : obj.function
+    if(typeof fn !== 'function') {
+        return
+    }
+    let functionArguments = obj.args
+    const context = obj.ignoreContext ? undefined : self
+    if(!functionArguments){
+        functionArguments = Array.from(args)
+    }
+    if(typeof functionArguments === 'object' && functionArguments.constructor === Array) {
+        fn.apply(context, functionArguments)
+    }
+}
+
+function overrideFunction(self, functionToReplace, {before, after}) {
+    const oldFunc = self[functionToReplace]
+    if(typeof oldFunc !== 'function'){
+        throw new Error('Original function not provided')
+    }
+    const newFunc = function(...args){
+        _callFunc(self, before, args)
+        oldFunc.apply(self, args)
+        _callFunc(self, after, args)
+    }
+    self[functionToReplace] = newFunc
+    return newFunc
+}
+
+if(typeof module !== 'undefined' && module.exports){
+    module.exports = overrideFunction
+} else if (typeof define === 'function' && define.amd) {
+    define(function () {
+        return config;
+    });
+} else {
+    global = (function () {
+        return this || (0, eval)('this');
+    }());
+    global.overrideFunction = overrideFunction
+}

test.js

@@ -0,0 +1,23 @@
+'use strict'
+const functionOverride = require('./index')
+
+const res = {
+    send: function(...args){
+        console.log(`res.send called with arguments -- ${args} -- and context ${JSON.stringify(this)}`)
+    },
+    a: 1
+}
+
+function before(...args){
+    console.log(`before called with arguments -- ${args} -- and context ${JSON.stringify(this)}`)
+}
+
+function after(...args) {
+    console.log(`after called with arguments -- ${args} -- and context ${JSON.stringify(this)}`)
+}
+
+before = before.bind(this, "before", "fdsfsdfdsfsdfdsfds")
+
+res.send = functionOverride(res, 'send', {before, after})
+
+res.send("dsa", "sfds")