Take away: Always check you ruturn the accumulator Always pass in the inital value var data = ["vote1", "vote2", "vote1", "vote2"]; var reducer = function(acc, value){ if(acc[value]){ acc[value] = acc[value] + 1; }e…
Learn a few advanced reduction patterns: flatten allows you to merge a set of arrays into a single array, the dreaded flatmap allows you to convert an array of objects into an array of arrays which then get flattened, and reduceRight allows you to in…
Learn how two common array functions - map() and filter() - are syntactic sugar for reduce operations. Learn how to use them, how to compose them, and how using reduce can give you a big performance boost over composing filters and maps over a large…
Sometimes we need to turn arrays into new values in ways that can't be done purely by passing an accumulator along with no knowledge about its context. Learn how to reduce an array of numbers into its mathematical mean in a single reduce step by usin…
Learn how to use array reduction to create functional pipelines by composing arrays of functions. const increase = (input) => { return input + 1; } const decrease = (input) => { return input - 1; } const double = (input) => { return input * 2; }…
http://devs.cloudimmunity.com/gotchas-and-common-mistakes-in-go-golang/ 50 Shades of Go: Traps, Gotchas, and Common Mistakes for New Golang Devs Go is a simple and fun language, but, like any other language, it has a few gotchas... Many of those gotc…
(Sorry for that click-bait heading. Couldn’t resist ;-) ) We’re on a mission. To teach you SQL. But mostly, we want to teach you how to appreciate SQL. You’ll love it! Getting SQL right or wrong shouldn’t be about that You’re-Doing-It-Wrong™ attitude…
原文  http://aotu.io/notes/2016/04/15/2016-04-14-js-reduce/   JavaScript中reduce()方法不完全指南 reduce() 方法接收一个函数作为累加器,数组中的每个值(从左到右)开始缩减,最终为一个值,是ES5中新增的又一个数组逐项处理方法,那reduce方法跟foreach.map等数组方法又有啥区别呢. arr.reduce(callback[, initialValue]) - More From MDN callback…
New and old users alike can run into a pitfall. Below we outline issues that we see frequently as well as explain how to resolve those issues. In the #nginx IRC channel on Freenode, we see these issues frequently. This Guide Says The most frequent is…
DOM 1. 节点 getElementsByName方法 <!DOCTYPE HTML> <html> <head> <script type="text/javascript"> function getnum(){ var mynode = document.getElementsByName("myt"); alert(mynode.length); } </script> </head>…