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nodejs漸入佳境[10]-案例-用戶輸入+json增刪查改

發(fā)布時(shí)間：2020-07-23 18:51:44 來(lái)源：網(wǎng)絡(luò) 閱讀：339 作者：jonson_jackson 欄目：開發(fā)技術(shù)

對(duì)于之前的代碼進(jìn)行封裝

原始文件app.js

對(duì)于返回節(jié)點(diǎn)進(jìn)行判斷，如果新增了節(jié)點(diǎn)，就打印新增節(jié)點(diǎn)。

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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:

封裝 獲取節(jié)點(diǎn)以及保存節(jié)點(diǎn)、返回節(jié)點(diǎn)。

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

//從文件中獲取節(jié)點(diǎn)
var fetchNode = ()=>{
  try{
    var notesString = fs.readFileSync('notes-data.json');
    return JSON.parse(notesString);
  }catch(e){
    return [];
  }
}
//保存節(jié)點(diǎn)到文件
var saveNote = (notes)=>{

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

}

//增加節(jié)點(diǎn)，如果新增返回新增節(jié)點(diǎn)。
var addNote = (title,body)=>{
  var notes = fetchNode();
  var note = {
      title,
      body
  };

  //篩選出相同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title===title);
  //沒(méi)有相同的節(jié)點(diǎn)
  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
};

測(cè)試

打開控制臺(tái)，在當(dāng)前目錄下輸入：

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

控制臺(tái)返回結(jié)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

移除節(jié)點(diǎn)

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');
//從文件中獲取節(jié)點(diǎn)
var fetchNode = ()=>{
  try{
    var notesString = fs.readFileSync('notes-data.json');
    return JSON.parse(notesString);
  }catch(e){
    return [];
  }
}
//保存節(jié)點(diǎn)到文件
var saveNote = (notes)=>{

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

}

//增加節(jié)點(diǎn)，如果新增返回新增節(jié)點(diǎn)。
var addNote = (title,body)=>{
  var notes = fetchNode();
  var note = {
      title,
      body
  };

  //篩選出相同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title===title);
  //沒(méi)有相同的節(jié)點(diǎn)
  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();
  //篩選出不同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title!==title);
    saveNote(duplicateNotes);
    return notes.length !==duplicateNotes.length;
};

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

測(cè)試2

打開控制臺(tái)，在當(dāng)前目錄下輸入：

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

控制臺(tái)返回結(jié)果并且josn文件中對(duì)應(yīng)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

獲取節(jié)點(diǎn)

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');
//從文件中獲取節(jié)點(diǎn)
var fetchNode = ()=>{
  try{
    var notesString = fs.readFileSync('notes-data.json');
    return JSON.parse(notesString);
  }catch(e){
    return [];
  }
}
//保存節(jié)點(diǎn)到文件
var saveNote = (notes)=>{

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

}

//增加節(jié)點(diǎn)，如果新增返回新增節(jié)點(diǎn)。
var addNote = (title,body)=>{
  var notes = fetchNode();
  var note = {
      title,
      body
  };

  //篩選出相同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title===title);
  //沒(méi)有相同的節(jié)點(diǎn)
  if(duplicateNotes.length ===0){
    notes.push(note);
    saveNote(notes);
    return note;
  }
}

var getAll = ()=>{

};

var getNote = (title)=>{

  var notes = fetchNode();
  //篩選出相同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title===title);
  return duplicateNotes[0];
};

var removeNote = (title)=>{
  var notes = fetchNode();
  //篩選出不同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title!==title);
    saveNote(duplicateNotes);
    return notes.length !==duplicateNotes.length;
};

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

測(cè)試3

打開控制臺(tái)，在當(dāng)前目錄下輸入：

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

控制臺(tái)返回結(jié)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

列出所有節(jié)點(diǎn)

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');
//從文件中獲取節(jié)點(diǎn)
var fetchNode = ()=>{
  try{
    var notesString = fs.readFileSync('notes-data.json');
    return JSON.parse(notesString);
  }catch(e){
    return [];
  }
}
//保存節(jié)點(diǎn)到文件
var saveNote = (notes)=>{

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

}

//增加節(jié)點(diǎn)，如果新增返回新增節(jié)點(diǎn)。
var addNote = (title,body)=>{
  var notes = fetchNode();
  var note = {
      title,
      body
  };

  //篩選出相同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title===title);
  //沒(méi)有相同的節(jié)點(diǎn)
  if(duplicateNotes.length ===0){
    notes.push(note);
    saveNote(notes);
    return note;
  }
}

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

var getNote = (title)=>{

  var notes = fetchNode();
  //篩選出相同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title===title);
  return duplicateNotes[0];
};

var removeNote = (title)=>{
  var notes = fetchNode();
  //篩選出不同的節(jié)點(diǎn)
  var duplicateNotes = notes.filter((note)=>note.title!==title);
    saveNote(duplicateNotes);
    return notes.length !==duplicateNotes.length;
};

測(cè)試4

打開控制臺(tái)，在當(dāng)前目錄下輸入：

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> node app.js list

控制臺(tái)返回結(jié)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' }

  • 本文鏈接： https://dreamerjonson.com/2018/11/14/node-10/

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