我有几个重新构造JSON文件的函数。他们彼此写作和操纵。它们在同一个js文件中。每个功能都取决于该功能才能正常运行。但是由于他们每个人都在读取文件后同步操作该文件，因此我遇到了一个难以解释的问题，因为我不确定我是否理解得很好。当第一个函数完成任务时，第二个函数无法读取它（它读取但看不到更新的对象及其属性）。如果我一个接一个地运行所有功能，然后重新启动程序，它的读取效果很好。这是我到目前为止尝试过的；
两者都不适合我。我在StackOverflow中阅读到它fs.watch可以帮助我，但找不到有关如何实现该功能的适当说明。我对此问题的任何帮助将不胜感激。
const fs = require('fs');
const ReadRawData= fs.readFileSync('Data.json');
const ReadParsed = JSON.parse(ReadRawData);
fs.watchFile('Data.json', (curr, prev) => {
console.log(`the current mtime is: ${curr.mtime}`);
console.log(`the previous mtime was: ${prev.mtime}`);
});
我只想知道每次文件更改后如何重新加载此ReadParsed，并且可以从函数访问重新加载的版本。
这是我的完整代码；这是testing2.js
const request = require('request');
const cherio= require('cheerio');
const fs = require('fs');
const cheerioTableparser = require('cheerio-tableparser');
async function htmlCollector () {
const ReadTransactionBase = await fs.readFileSync('transactionDatabase.json');
const ReadTransaction = JSON.parse(ReadTransactionBase);
ReadTransaction.pageInformation = "";
let editedDataBase = JSON.stringify(ReadTransaction, null, 2);
fs.writeFileSync('transactionDatabase.json', editedDataBase);
for (let counter = 1; counter <= ReadTransaction.maxPage; counter++) {
request(ReadTransaction.link + counter,
(error, response, html) => {
if (!error && response.statusCode === 200) {
const $ = cherio.load(html);
const items = [];
$('#maindiv').each(function (i, elem) {
items[i] = $(this).html();
});
let newPage = {['PageNumber'+counter] : items};
ReadTransaction.pageInformation = Object.assign(newPage,ReadTransaction.pageInformation);
let editedDataBase = JSON.stringify(ReadTransaction, null, 2);
fs.writeFileSync('transactionDatabase.json', editedDataBase);
}
})
}
}
async function databaseModifier () {
const ReadTransactionBase = await fs.readFileSync('transactionDatabase.json');
const ReadTransaction = JSON.parse(ReadTransactionBase);
delete ReadTransaction.from;
delete ReadTransaction.quantities;
delete ReadTransaction.orangeBox;
let editedDataBase = JSON.stringify(ReadTransaction, null, 2);
console.log('test');
fs.writeFileSync('transactionDatabase.json', editedDataBase);
for (let i=1; i<=Object.keys(ReadTransaction.pageInformation).length;i++) {
let nums = 'PageNumber' + i;
let newObject = {[nums]: {}};
ReadTransaction.from = Object.assign(newObject,ReadTransaction.from);
ReadTransaction.orangeBox = Object.assign(newObject,ReadTransaction.orangeBox);
ReadTransaction.quantities = Object.assign(newObject,ReadTransaction.quantities);
let editedDataBase = JSON.stringify(ReadTransaction, null, 2);
fs.writeFileSync('transactionDatabase.json', editedDataBase);
}
}
async function fromOrangeBoxQuantities () {
const ReadTransactionBase = await fs.readFileSync('transactionDatabase.json');
const ReadTransaction = JSON.parse(ReadTransactionBase);
for (let counter = 1; counter <= ReadTransaction.maxPage ; counter++) {
let HTMLPageNumber = 'PageNumber' + counter;
let $ = cherio.load(ReadTransaction.pageInformation[HTMLPageNumber][0]);
cheerioTableparser($);
let data = $('.table').parsetable(true,true,true);
for (let sCounter = 1; sCounter <= data[2].length; sCounter++) {
let fromTable = {[sCounter] : [data[2][sCounter-1]]};
let orangeBoxTable = {[sCounter] : [data[3][sCounter-1]]};
let quantityTable = {[sCounter] : [data[5][sCounter-1]]};
ReadTransaction.from[HTMLPageNumber] = Object.assign(fromTable,ReadTransaction.from[HTMLPageNumber]);
ReadTransaction.orangeBox[HTMLPageNumber] = Object.assign(orangeBoxTable,ReadTransaction.orangeBox[HTMLPageNumber]);
ReadTransaction.quantities[HTMLPageNumber] = Object.assign(quantityTable,ReadTransaction.quantities[HTMLPageNumber]);
let editedDataBase = JSON.stringify(ReadTransaction, null, 2);
fs.writeFileSync('transactionDatabase.json', editedDataBase);
}
}
}
async function validatorOfTransactions (){
const ReadTransactionBase = await fs.readFileSync('transactionDatabase.json');
const ReadTransaction = JSON.parse(ReadTransactionBase);
ReadTransaction.validQuantities = [];
let editedDataBase = JSON.stringify(ReadTransaction, null, 2);
fs.writeFileSync('transactionDatabase.json', editedDataBase);
for (let counter = 1; counter <= ReadTransaction.maxPage ; counter++) {
let HTMLPageNumber = 'PageNumber' + counter;
let length = Object.keys(ReadTransaction.from[HTMLPageNumber]).length;
for (let sCounter = 1; sCounter <= length; sCounter++) {
let a = ReadTransaction.from[HTMLPageNumber][sCounter].toString();
let b = ReadTransaction.fromAddress;
let c = ReadTransaction.orangeBox[HTMLPageNumber][sCounter].toString();
let d = ReadTransaction.OrangeBox;
if (a === b && c === d) {
console.log('yay');
ReadTransaction.validQuantities.push(parseFloat(ReadTransaction.quantities[HTMLPageNumber][sCounter].toString().replace(/,/g,'')));
let editedDataBase = JSON.stringify(ReadTransaction, null, 2);
fs.writeFileSync('transactionDatabase.json', editedDataBase);
}
}
}
}
async function finalizeCalculation () {
const ReadTransactionBase = await fs.readFileSync('transactionDatabase.json');
const ReadTransaction = JSON.parse(ReadTransactionBase);
let NewArray = ReadTransaction.validQuantities;
return NewArray.reduce((a,b) => a +b, 0);
}
module.exports = {
htmlCollector : htmlCollector,
databaseModifier : databaseModifier,
fromOrangeBoxQuantities : fromOrangeBoxQuantities,
validatorOfTransactions : validatorOfTransactions,
finalizeCalculation : finalizeCalculation
};
这是transactionDatabase.json;
{
"link": "https://etherscan.io/token/generic-tokentxns2?contractAddress=0xaf2de5cb07d8f5de2369ff104150fef9dc0e604b&mode=&a=0x11209cbc2ea8cf829aa5aa1cdc5a4e5962e70655&p=",
"maxPage": 12,
"fromAddress": "0x11209cbc2ea8cf829aa5aa1cdc5a4e5962e70655",
"OrangeBox": "OUT",
"validQuantities": [],
"pageInformation": {}
}
这是newtest.js;
let testing2 = require('./testing2');
testing2.htmlCollector().then(() => testing2.databaseModifier().then(()=> testing2.fromOrangeBoxQuantities().then(()=> testing2.validatorOfTransactions().then())));
这是我遇到的错误；
（节点：21760）UnhandledPromiseRejectionWarning：TypeError：无法读取未定义的属性“ 0”