nodejs渐入佳境[10]-案例-用户输入+json增删查改-创新互联

对于之前的代码进行封装

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原始文件app.js

对于返回节点进行判断,如果新增了节点,就打印新增节点。

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//打印字符串
const yargs = require('yargs');
const nodes = require('./nodes.js')
console.log('Start app.');

console.log(process.argv);

console.log('yargs',yargs.argv);
const argv = yargs.argv;
var command = process.argv[2];

if(command==='add'){
  var note = nodes.addNote(argv.title,argv.body);
 if(note){
   console.log('add success');
   console.log(`title:${note.title}`);
   console.log(`body:${note.body}`);
 }
}else if(command === 'list'){
 nodes.getAll();

}else if(command =='read'){
 nodes.getNote(argv.title);
}else if(command=='remove'){
 nodes.removeNote(argv.title);
}else{
 console.log('command not find');
}

notes.js:

封装 获取节点以及保存节点、返回节点。

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console.log('start nodes.js');
const fs = require('fs');

//从文件中获取节点
var fetchNode = ()=>{
 try{
   var notesString = fs.readFileSync('notes-data.json');
   return JSON.parse(notesString);
 }catch(e){
   return [];
 }
}
//保存节点到文件
var saveNote = (notes)=>{

 fs.writeFileSync('notes-data.json',JSON.stringify(notes));

}

//增加节点,如果新增返回新增节点。
var addNote = (title,body)=>{
 var notes = fetchNode();
 var note = {
     title,
     body
 };

 //筛选出相同的节点
 var duplicateNotes = notes.filter((note)=>note.title===title);
 //没有相同的节点
 if(duplicateNotes.length ===0){
   notes.push(note);
   saveNote(notes);
   return note;
 }
}

var getAll = ()=>{
console.log('Get All notes');
};

var getNote = (title)=>{

 console.log('getting note',title);
};

var removeNote = (title)=>{
 console.log('Removing note',title);
};

module.exports = {
   addNote,
   getAll,
   getNote,
   removeNote
};

测试

打开控制台,在当前目录下输入:

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> node app.js add --title="buy book3" --body="jonson"

控制台返回结果:

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start nodes.js
Start app.
[ '/Users/jackson/.nvm/versions/node/v10.13.0/bin/node',
 '/Users/jackson/Desktop/compaign/app.js',
 'add',
 '--title=buy book3',
 '--body=jonson' ]
yargs { _: [ 'add' ],
 title: 'buy book3',
 body: 'jonson',
 '$0': 'app.js' }
add success
title:buy book3
body:jonson

移除节点

app.js:

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//打印字符串
const yargs = require('yargs');
const nodes = require('./nodes.js')
console.log('Start app.');

console.log(process.argv);

console.log('yargs',yargs.argv);
const argv = yargs.argv;
var command = process.argv[2];

if(command==='add'){
  var note = nodes.addNote(argv.title,argv.body);
 if(note){
   console.log('add success');
   console.log(`title:${note.title}`);
   console.log(`body:${note.body}`);
 }
}else if(command === 'list'){
 nodes.getAll();

}else if(command =='read'){
 nodes.getNote(argv.title);
}else if(command=='remove'){
 var noteRemoved =  nodes.removeNote(argv.title);
 var message = noteRemoved?'Note was removed':'note not found';
 console.log(message);
}else{
 console.log('command not find');
}

notes.js:

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console.log('start nodes.js');
const fs = require('fs');
//从文件中获取节点
var fetchNode = ()=>{
 try{
   var notesString = fs.readFileSync('notes-data.json');
   return JSON.parse(notesString);
 }catch(e){
   return [];
 }
}
//保存节点到文件
var saveNote = (notes)=>{

 fs.writeFileSync('notes-data.json',JSON.stringify(notes));

}

//增加节点,如果新增返回新增节点。
var addNote = (title,body)=>{
 var notes = fetchNode();
 var note = {
     title,
     body
 };

 //筛选出相同的节点
 var duplicateNotes = notes.filter((note)=>note.title===title);
 //没有相同的节点
 if(duplicateNotes.length ===0){
   notes.push(note);
   saveNote(notes);
   return note;
 }
}

var getAll = ()=>{
console.log('Get All notes');
};

var getNote = (title)=>{

 console.log('getting note',title);
};

var removeNote = (title)=>{
 var notes = fetchNode();
 //筛选出不同的节点
 var duplicateNotes = notes.filter((note)=>note.title!==title);
   saveNote(duplicateNotes);
   return notes.length !==duplicateNotes.length;
};

module.exports = {
   addNote,
   getAll,
   getNote,
   removeNote
};

测试2

打开控制台,在当前目录下输入:

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> node app.js remove --title="buy book2"

控制台返回结果并且josn文件中对应元素被移除:

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start nodes.js
Start app.
[ '/Users/jackson/.nvm/versions/node/v10.13.0/bin/node',
 '/Users/jackson/Desktop/compaign/app.js',
 'remove',
 '--title=buy book2' ]
yargs { _: [ 'remove' ], title: 'buy book2', '$0': 'app.js' }
Note was removed

获取节点

app.js

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//打印字符串
const yargs = require('yargs');
const nodes = require('./nodes.js')
console.log('Start app.');

console.log(process.argv);

console.log('yargs',yargs.argv);
const argv = yargs.argv;
var command = process.argv[2];

if(command==='add'){
  var note = nodes.addNote(argv.title,argv.body);
 if(note){
   console.log('add success');
   console.log(`title:${note.title}`);
   console.log(`body:${note.body}`);
 }
}else if(command === 'list'){
 nodes.getAll();

}else if(command =='read'){
 var note = nodes.getNote(argv.title);
 if(note){
   console.log('find');
   console.log(`title:${note.title}`);
   console.log(`body:${note.body}`);
 }else{
   console.log('note not found');
 }
}else if(command=='remove'){
 var noteRemoved =  nodes.removeNote(argv.title);
 var message = noteRemoved?'Note was removed':'note not found';
 console.log(message);
}else{
 console.log('command not find');
}

notes.js:

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console.log('start nodes.js');
const fs = require('fs');
//从文件中获取节点
var fetchNode = ()=>{
 try{
   var notesString = fs.readFileSync('notes-data.json');
   return JSON.parse(notesString);
 }catch(e){
   return [];
 }
}
//保存节点到文件
var saveNote = (notes)=>{

 fs.writeFileSync('notes-data.json',JSON.stringify(notes));

}

//增加节点,如果新增返回新增节点。
var addNote = (title,body)=>{
 var notes = fetchNode();
 var note = {
     title,
     body
 };

 //筛选出相同的节点
 var duplicateNotes = notes.filter((note)=>note.title===title);
 //没有相同的节点
 if(duplicateNotes.length ===0){
   notes.push(note);
   saveNote(notes);
   return note;
 }
}

var getAll = ()=>{

};

var getNote = (title)=>{

 var notes = fetchNode();
 //筛选出相同的节点
 var duplicateNotes = notes.filter((note)=>note.title===title);
 return duplicateNotes[0];
};

var removeNote = (title)=>{
 var notes = fetchNode();
 //筛选出不同的节点
 var duplicateNotes = notes.filter((note)=>note.title!==title);
   saveNote(duplicateNotes);
   return notes.length !==duplicateNotes.length;
};

module.exports = {
   addNote,
   getAll,
   getNote,
   removeNote
};

测试3

打开控制台,在当前目录下输入:

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> node app.js read  --title="buy book3"

控制台返回结果:

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start nodes.js
Start app.
[ '/Users/jackson/.nvm/versions/node/v10.13.0/bin/node',
 '/Users/jackson/Desktop/compaign/app.js',
 'read',
 '--title=buy book3',
 '--body=123' ]
yargs { _: [ 'read' ], title: 'buy book3', body: 123, '$0': 'app.js' }
find
title:buy book3
body:jonson

列出所有节点

app.js

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//打印字符串
const yargs = require('yargs');
const nodes = require('./nodes.js')
console.log('Start app.');

console.log(process.argv);

console.log('yargs',yargs.argv);
const argv = yargs.argv;
var command = process.argv[2];

if(command==='add'){
  var note = nodes.addNote(argv.title,argv.body);
 if(note){
   console.log('add success');
   console.log(`title:${note.title}`);
   console.log(`body:${note.body}`);
 }
}else if(command === 'list'){
   var allnotes =  nodes.getAll();
   allnotes.forEach((note)=>{  console.log(note)});
}else if(command =='read'){
 var note = nodes.getNote(argv.title);
 if(note){
   console.log('find');
   console.log(`title:${note.title}`);
   console.log(`body:${note.body}`);
 }else{
   console.log('note not found');
 }
}else if(command=='remove'){
 var noteRemoved =  nodes.removeNote(argv.title);
 var message = noteRemoved?'Note was removed':'note not found';
 console.log(message);
}else{
 console.log('command not find');
}

nodes.js

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console.log('start nodes.js');
const fs = require('fs');
//从文件中获取节点
var fetchNode = ()=>{
 try{
   var notesString = fs.readFileSync('notes-data.json');
   return JSON.parse(notesString);
 }catch(e){
   return [];
 }
}
//保存节点到文件
var saveNote = (notes)=>{

 fs.writeFileSync('notes-data.json',JSON.stringify(notes));

}

//增加节点,如果新增返回新增节点。
var addNote = (title,body)=>{
 var notes = fetchNode();
 var note = {
     title,
     body
 };

 //筛选出相同的节点
 var duplicateNotes = notes.filter((note)=>note.title===title);
 //没有相同的节点
 if(duplicateNotes.length ===0){
   notes.push(note);
   saveNote(notes);
   return note;
 }
}

var getAll = ()=>{
 var notes = fetchNode();
 return notes;
};

var getNote = (title)=>{

 var notes = fetchNode();
 //筛选出相同的节点
 var duplicateNotes = notes.filter((note)=>note.title===title);
 return duplicateNotes[0];
};

var removeNote = (title)=>{
 var notes = fetchNode();
 //筛选出不同的节点
 var duplicateNotes = notes.filter((note)=>note.title!==title);
   saveNote(duplicateNotes);
   return notes.length !==duplicateNotes.length;
};

测试4

打开控制台,在当前目录下输入:

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> node app.js list

控制台返回结果:

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start nodes.js
Start app.
[ '/Users/jackson/.nvm/versions/node/v10.13.0/bin/node',
 '/Users/jackson/Desktop/compaign/app.js',
 'list' ]
yargs { _: [ 'list' ], '$0': 'app.js' }
{ title: 'buy book3', body: 'jonson' }
{ title: 'buy book2', body: 'jonson' }
  • 本文链接: https://dreamerjonson.com/2018/11/14/node-10/

  • 版权声明: 本博客所有文章除特别声明外,均采用 CC BY 4.0 CN协议 许可协议。转载请注明出处!

nodejs渐入佳境[10]-案例-用户输入+json增删查改

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