如何从存档文件中的 json 中读取特定值。使用 javascript 和 jszip
how to read specific value from json in an archived file. Using javascript ,and jszip
我正在使用 jszip 从 zip 文件中读取 json 文件。我可以打开它并从我的函数中获取我想要的信息到控制台。但是,我无法从 javascript 函数中获取该信息。也许我做错了。平时不用js写代码。
const JSZip = require("jszip");
const fs = require("fs");
var myReturn;
function readJsons(bookPath,bookName,fileName,filePath,keyOption){
fs.readFile(bookPath + bookName, function(err, data) {
if (err) throw err;
JSZip.loadAsync(data).then(function (zip) {
// Read the contents of the '.txt' file
zip.file(filePath + fileName).async("string").then(function (data) {
var mydata = JSON.parse(data);
//gets the value of the key entered
myReturn = JSON.stringify(mydata[0][keyOption]); //value here should be "test book"
console.log(myReturn); //printed in console is "test book" works to here
return myReturn;
});
});
});
}
console.log(readJsons('simplelbook.zip','','frontMatter.json','','bookName'));
问题是您在回调内部返回,所以您没有在实际函数中返回。解决方案是使用 async/await 代替:
const JSZip = require("jszip");
const fs = require("fs");
const util = require("util"); // require the util module
const readFile = util.promisify(fs.readFile); // transform fs.readFile into a more compatible form
async function readJsons(bookPath, bookName, fileName, filePath, keyOption) {
try {
// this part does the same thing, but with different syntax
const data = await readFile(bookPath + bookName);
const zip = await JSZip.loadAsync(data);
const jsonData = await zip.file(filePath + fileName).async("string");
const mydata = JSON.parse(jsonData);
const myReturn = JSON.stringify(mydata[0][keyOption]);
return myReturn; // return the data, simple as that
} catch (e) {
console.error(e); // error handling
}
}
(async () => { // self executing async function so we can use await
console.log(
await readJsons("simplelbook.zip", "", "frontMatter.json", "", "bookName")
);
})()
注意我已经导入了 util
模块来将 fs.readFile
变成一个更适合 async/await 的函数 :)
我正在使用 jszip 从 zip 文件中读取 json 文件。我可以打开它并从我的函数中获取我想要的信息到控制台。但是,我无法从 javascript 函数中获取该信息。也许我做错了。平时不用js写代码。
const JSZip = require("jszip");
const fs = require("fs");
var myReturn;
function readJsons(bookPath,bookName,fileName,filePath,keyOption){
fs.readFile(bookPath + bookName, function(err, data) {
if (err) throw err;
JSZip.loadAsync(data).then(function (zip) {
// Read the contents of the '.txt' file
zip.file(filePath + fileName).async("string").then(function (data) {
var mydata = JSON.parse(data);
//gets the value of the key entered
myReturn = JSON.stringify(mydata[0][keyOption]); //value here should be "test book"
console.log(myReturn); //printed in console is "test book" works to here
return myReturn;
});
});
});
}
console.log(readJsons('simplelbook.zip','','frontMatter.json','','bookName'));
问题是您在回调内部返回,所以您没有在实际函数中返回。解决方案是使用 async/await 代替:
const JSZip = require("jszip");
const fs = require("fs");
const util = require("util"); // require the util module
const readFile = util.promisify(fs.readFile); // transform fs.readFile into a more compatible form
async function readJsons(bookPath, bookName, fileName, filePath, keyOption) {
try {
// this part does the same thing, but with different syntax
const data = await readFile(bookPath + bookName);
const zip = await JSZip.loadAsync(data);
const jsonData = await zip.file(filePath + fileName).async("string");
const mydata = JSON.parse(jsonData);
const myReturn = JSON.stringify(mydata[0][keyOption]);
return myReturn; // return the data, simple as that
} catch (e) {
console.error(e); // error handling
}
}
(async () => { // self executing async function so we can use await
console.log(
await readJsons("simplelbook.zip", "", "frontMatter.json", "", "bookName")
);
})()
注意我已经导入了 util
模块来将 fs.readFile
变成一个更适合 async/await 的函数 :)