In this lesson we'll take some existing code and refactor it using some functions from the Ramda library, most notably, compose and converge. When we're done, we'll have taken a function with a couple of local variables and parameter references and c…

Most of the functions offered by the ramda library are curried by default. Functions you've created or that you've pulled in from another library may not be curried. Ramda's curry and curryN functions allow you to take a non-curried function and use…

In this lesson we'll see how Ramda's path and pathOr functions can be used to safely access a deeply nested property from an object while avoiding the dreaded checks for undefined at each new property in the desired path. const R = require('ramda');…

In this lesson, we'll look at how we can use Ramda's invoker and constructNfunctions to take methods of an object and turn them into reusable utility functions that are curried and accept their object as the last argument. We'll convert a dot-chained…

Naming things is hard and arguments in generic utility functions are no exception. Making functions "tacit" or "point free" removes the need for the extra parameter names and can make your code cleaner and more succinct. In this lesson…

Promise chains can be a powerful way to handle a series of transformations to the results of an async call. In some cases, additional promises are required along the way. In cases where there are no new promises, function composition can reduce the n…

When doing comparisons inside of functions, you end of relying heavily on the argument passed into the function. Ramda's converge allows you to do comparisons in a Point-Free style allowing you more flexibility with composing and constructing functio…

You can really unlock the power of ramda (and functional programming in general) when you combine functions. Counting words in a string may seem like a relatively difficult task, but ramda makes it easy by providing a countBy function. This lesson wa…

In this lesson, we'll refactor a React component to use Ramda lenses to update our component state. We'll create a lens to focus on the property we want to target and use over to apply the existing state value to a utility function and we'll get back…

Sometimes you just need a subset of an object. In this lesson, we'll cover how you can accomplish this using Ramda's pick and omit functions, as well as the pickAll and pickBy variants of pick. const R = require('ramda'); const {pick, prop, pickBy, p…

In this lesson you will create a utility function that allows you to quickly compose behavior of multiple functions to create new behavior. By the end, you will have successfully created a tremendously popular helper function that is used in JavaScri…

在ES6模块解决方案出现之前,工具库或包常用三种解决方案提供对外使用的接口,最早是直接暴露给全局变量,比如我们熟知的Jquery暴露的全局变量是$,Lodash对外暴露的全局变量是_,后来出现了AMD和CommonJS(CMD的一种实现)两种常用的模块解决方案.  全局变量 // MyDependency is in your global scope var MyModule = function() { MyDependency.xxx() }; CommonJS var MyDepend…

函数式编程中有一种模式是通过组合多个函数的功能来实现一个组合函数.一般支持函数式编程的工具库都实现了这种模式,这种模式一般被称作compose与pipe.以函数式著称的Ramda工具库为例. const R = require('ramda'); function inc (num) { return ++num; } const fun1 = R.compose(Math.abs, inc, Math.pow) const fun2 = R.pipe(Math.pow, Math.abs, i…

译者按: 你可能已经用到Underscore或者Lodash.本文列举了13个常用的JavaScript工具库来提高开发效率. 原文: 11 Javascript Utility Libraries You Should Know In 2018 译者: Fundebug 为了保证可读性,本文采用意译而非直译.另外,本文版权归原作者所有,翻译仅用于学习. JavaScript依然是2018年最受欢迎.最流行的编程语言,所以它的生态系统也十分完善. JavaScript小小的标准库已经不足以应付各…

网址: https://www.spinellis.gr/cscout/ https://www2.dmst.aueb.gr/dds/cscout/index.html https://github.com/dspinellis/cscout 还有一个工具叫Xrefactory,它可以分析c++程序. cscout只能分析c程序.具体如下: A tool adopting an approach similar to ours is Vittek's Xrefactory [59]. Its f…

// Underscore.js 1.8.3 // http://underscorejs.org // (c) 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors // Underscore may be freely distributed under the MIT license. // 中文注释 by hanzichi @https://github.com/hanzichi //…

// Underscore.js 1.8.3 // http://underscorejs.org // (c) 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors // Underscore may be freely distributed under the MIT license. // 中文注释 by hanzichi @https://github.com/hanzichi //…

object wb{ def main(args:Array[String]){ println("Happy everyday!DATA-CENTER!") println(new java.util.Date()) } object w{ def main(args:Array[String]){ println("Happy everyday!") } } ~ ~ ~ Scala集成了函数编程和对象编程的优点. SEAMLESS JAVA INTEROP Sc…

When you want to build your logic with small, composable functions you need a functional way to handle conditional logic. You could wrap ternary expressions and if/else statements in functions, handling all of the concerns around data mutation yourse…

We'll learn how to take advantage of Ramda's automatic function currying and data-last argument order to combine a series of pure functions into a left-to-right composition, or pipeline, with Ramda's pipe function. A simple example will take 'teams'…

0x00 何为函数式编程 网上已经有好多详细的接受了,我认为比较重要的有: 函数是"第一等公民",即函数和其它数据类型一样处于平等地位 使用"表达式"(指一个单纯的运算过程,总是有返回值),而不是"语句"(执行操作,没有返回值) 没有"副作用",即不修改外部值 0x01 开始函数式编程 在此之前,请先了解PHP中的匿名函数和闭包,可以参考我写得博客 函数式编程有两个最基本的运算:合成和柯里化. 函数合成 函数合成,即把多个函数…

In this lesson we'll take a stateful React component and look at how we can refactor our setState calls to use an updater function and then leverage Ramda's evolvefunction to make our updater function a reusable utility that isn't tied to the React A…

In this lesson we'll use a handful of Ramda's utility functions to take a queryString full of name/value pairs and covert it into a JavaScript object so we can access those properties in a more useful way. Along the way, we'll build up a composition…

In this lesson, we'll use Promise.all to get an array that contains the resolved values from multiple promises. Then we'll see how we can use Ramda to convert that array of values into a single object using zip with fromPairs. Then we'll refactor to…

In this lesson, we'll filter a list of objects based on multiple conditions and we'll use Ramda's allPass function to create a joint predicate from multiple, individual predicate functions. const R = require('ramda'); const { allPass, propEq, lte, pr…

In this lesson we'll take an array of objects and map it to a new array where each object is a subset of the original. We'll look at multiple ways to accomplish this, refactoring our code into a simple and easy to read function using Ramda's map, pic…

Handling your logic with composable functions makes your code declarative, leading to code that's easy to read and easy to test. Breaking that up to wrap some risky function in a try/catch block introduces imperative code and makes it harder to maint…

We'll learn how to get a subset of an array by specifying items to include with filter, or items to exclude using reject. We'll also look at how to get the results from both filter and reject, neatly separated with partition. // we don't need to requ…

学习函数式编程的过程中,我接触到了 Ramda.js. 我发现,这是一个很重要的库,提供了许多有用的方法,每个 JavaScript 程序员都应该掌握这个工具. 你可能会问,Underscore 和 Lodash 已经这么流行了,为什么还要学习好像雷同的 Ramda 呢? 回答是,前两者的参数位置不对,把处理的数据放到了第一个参数. var square = n => n * n; _.map([4, 8], square) // [16, 64] 上面代码中,_.map的第一个参数[4, 8]…

Ramda 基本的数据结构都是原生 JavaScript 对象,我们常用的集合是 JavaScript 的数组.Ramda 还保留了许多其他原生 JavaScript 特性,例如,函数是具有属性的对象. 今天我来说说javascript函数式的方法库--Ramda.Ramda主要特性如下: Ramda 强调更加纯粹的函数式风格.数据不变性和函数无副作用是其核心设计理念.这可以帮助你使用简洁.优雅的代码来完成工作. Ramda 函数本身都是自动柯里化的.这可以让你在只提供部分参数的情况下,轻松地在…