util-ex

Enhanced utils

This package modifies and enhances the standard util from node.js

API

Full API Documents is here: Docs

inject

▸ inject(aOrgFunc, aBeforeExec, aAfterExec): Function

Wraps a function and executes code before and/or after the wrapped function.

Throws

If aAfterExec is not a function and an error occurs while executing the wrapped function.

Example

1import { inject as injectFunc } from 'util-ex'
2
3// Wrapping a function with injectFunc
4const originalFunc = (a, b) => a + b;
5const beforeFunc = (a, b) => console.log(`Before execution: a = ${a}, b = ${b}`);
6const afterFunc = (result) => console.log(`After execution: result = ${result}`);
7const wrappedFunc = injectFunc(originalFunc, beforeFunc, afterFunc);
8const result = wrappedFunc(1, 2); // Logs "Before execution: a = 1, b = 2" and "After execution: result = 3"

Example

1// Wrapping a function with injectFunc and modifying arguments and return value
2const Arguments = injectFunc.Arguments
3const originalFunc = (a, b) => a + b;
4const beforeFunc = (a, b) => {
5  console.log(`Before execution: a = ${a}, b = ${b}`);
6  return new Arguments([a * 2, b * 3]);
7};
8const afterFunc = (result, isDenied) => {
9  console.log(`After execution: result = ${result}, isDenied = ${isDenied}`);
10  return result * 2;
11};
12const wrappedFunc = injectFunc(originalFunc, beforeFunc, afterFunc);
13const result = wrappedFunc(1, 2); // Logs "Before execution: a = 1, b = 2", "After execution: result = 6, isDenied = false"
14console.log(result); // Output: 12

Example

1// Wrapping a function with injectFunc and not executing the original function
2const originalFunc = (a, b) => a + b;
3const beforeFunc = (a, b) => {
4  console.log(`Before execution: a = ${a}, b = ${b}`);
5  return "Not executing original function";
6};
7const afterFunc = (result, isDenied) => {
8  console.log(`After execution: result = ${result}, isDenied = ${isDenied}`);
9  return "Modified return value";
10};
11const wrappedFunc = injectFunc(originalFunc, beforeFunc, afterFunc);
12const result = wrappedFunc(1, 2); // Logs "Before execution: a = 1, b = 2", "After execution: result = Modified return value, isDenied = true"
13console.log(result); // Output: "Modified return value"

Example

1// Wrapping a function with injectFunc and getting the original function's error
2const originalFunc = () => {
3  throw new Error("Original function error");
4};
5const beforeFunc = () => {
6  console.log("Before execution");
7};
8const afterFunc = (result, isDenied) => {
9  console.log(`After execution: result = ${result}, isDenied = ${isDenied}`);
10};
11const wrappedFunc = injectFunc(originalFunc, beforeFunc, afterFunc);
12wrappedFunc(); // Logs "Before execution", "After execution: result = [Error: Original function error], isDenied = false"

inject Parameters

Name	Type	Description
aOrgFunc	Function	The function to be wrapped.
aBeforeExec	Function	A function to be executed before the wrapped function aOrgFunc.
aAfterExec	Function	A function to be executed after the wrapped function aOrgFunc.

inject Returns

Function

A new function that wraps the original function.

BeforeExec: If aBeforeExec is a function, it will be called with the same context and arguments as the wrapped function.

• If it returns an Arguments object, the wrapped function will be called with the modified arguments.
• If it returns a value other than undefined, the wrapped function will not be called and this value will be returned as result instead.

AfterExec: If aAfterExec is a function, it will be called with the same context, arguments with additional the result of the aOrgFunc and isDenied flag.

• If the aOrgFunc throws an error, the result parameter will be an Error object.
• If aAfterExec returns a value, it will be used as the final result of the wrapped function.
• If isDenied parameter is true, it means aOrgFunc was not called during execution of the wrapped function.

injectMethod

▸ injectMethod(aObject, aMethodName, aNewMethod): boolean

Injects method into an object. optionally preserving access to the original method via "super" and original instance via "self".

Note:

• In the new method, you can use this.super() to call the original method, this.super() is already bound with original instance.
• The this[aMethodName] is also the original method, but not bound yet.
• this.self is the original instance!

Example

1import { injectMethod } from 'util-ex'
2
3var obj = {
4  method1: function() {
5    console.log('Hello');
6  }
7};
8
9var newMethod = function() {
10  this.super();
11  console.log('World');
12};
13
14injectMethod(obj, 'method1', newMethod);
15
16obj.method1(); // Output: Hello\nWorld

injectMethod Parameters

Name	Type	Description
aObject	any	the target object to inject
aMethodName	string	the target method to inject
aNewMethod	Function	the new method to be injected into the aObject.

injectMethod Returns

boolean

whether the injection is successful.

newFunction

newFunction(name, arguments, body[, scope[, values]])
newFunction(functionString[, scope[, values]])

Creates a new function with the given name, arguments, body, scope and values.

• If only one argument is provided and it is a function, returns a new function with the same code.
• If only one argument is provided and it is not a function, returns a new empty function with the given name.
• If multiple arguments are provided, creates a new function with the given name, arguments and body.

1import { newFunction } from 'util-ex'
2
3var fn = newFunction('yourFuncName', ['arg1', 'arg2'], 'return log(arg1+arg2);', {log:console.log})
4newFunction('function yourFuncName(){}')
5newFunction('function yourFuncName(arg1, arg2){return log(arg1+arg2);}', {log:console.log})
6newFunction('function yourFuncName(arg1, arg2){return log(arg1+arg2);}', ['log'], [console.log])
7
8//fn.toString() is :
9/*
10 "function yourFuncName(arg1, arg2) {
11    return log(arg1+arg2);
12 }"
13*/

defineProperty

defineProperty(object, key, value[, aOptions])

Define a property on the object. move to inherits-ex package.

usage

1const defineProperty = require('util-ex/lib/defineProperty')
2
3let propValue = ''
4const obj = {}
5
6defineProperty(obj, 'prop', 'simpleValue')
7defineProperty(obj, 'prop', undefined, {
8  get() {return propValue}
9  set(value) {propValue = value}
10})