练习题目需求：

我想要一个nodejs小程序，
它可以帮我处理一段字符串信息，这段字符串信息是由英文单词组成，每两个单词之间有空格，
处理结果也为一段字符串，这个字符串应该每行只显示一个单词和它的数量，并且按出现频率倒序排列

Example

input:

“it was the age of wisdom it was the age of foolishness it is”

output

it 3
was 2
the 2
age 2
of 2
wisdom 1
foolishness 1
is 1

Tasking 流程图

流程图

代码：

main.js

var format = function (word,count){
return word +" "+ count;
};
var group = function(wordArray){
return wordArray.reduce((array,word) => {
let entry = array.find((e) =>e.word ===word);
if(entry){
entry.count++;
}else{
array.push({word:word,count:1});
}
return array;
},[]);
};
var split = function(words){
return words.split(/\s+/);
};
var sort = function(groupedWords){
groupedWords.sort((s,y)=>y.count - x.count);
};
function main(words){
if(words!== ''){
let wordArray = words.split(/\s+/);
let groupedWords = group(wordArray);
groupedWords.sort((x,y) =>y.count -x.count);
return groupedWords.map((e) => format(e.word,e.count)).join('\r\n');
}
return '';
}
module.exports = main;

Frequency NumberSpec.js

var main = require("./main.js");
describe("Word Frequency",function(){
it("returns empty string given empty string",function(){
var result = main('');

    expect(result).toEqual('');
});
it("returns string given one word",function(){
    var result = main('he');
    expect(result).toEqual('he 1');
});
 it("returns string given two different words",function(){
    var result = main('he is');
    expect(result).toEqual('he 1\r\nis 1');
});
it("returns string given duplicated words",function(){
    var result = main('he is he');
    expect(result).toEqual('he 2\r\nis 1');
});
it("returns string given duplicated words need to be sorted",function(){
    var result = main('he is is');
    expect(result).toEqual('is 2\r\nhe 1');
});
it("returns string given words splited by multiple spaces",function(){
    var result = main('he       is');
    expect(result).toEqual('he 1\r\nis 1');
});
it("returns string given words splited by multiple spaces",function(){
    var result = main('it was the age of wisdom it was the age of foolishness it is');
    expect(result).toEqual('it 3\r\nwas 2\r\nthe 2\r\nage 2\r\nof 2\r\nwisdom 1\r\nfoolishness 1\r\nis 1');
});

});

GIT 截图

1.png

jasmint截图

2.png

个人总结

有难度，第一是安装git和nodejs，熟悉git和npm的各种操作指令，再有就是JS的语法，完成题目功能的逻辑反倒是比较好想，先传入字符串，开始按照空格分割，然后计数，排序再输出，意外经朋友提醒看到了教练在B站直播的视频，其中就有关于这个题目的讲解，认真看了，再写代码感觉轻松多了，关于TDD模式的编程也理解得更深深刻，还需要继续努力。