node.js 检查 writeFileSync 是否成功写入文件
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Checking if writeFileSync successfully wrote the file
提问by jolt
I have a simple route defined with express.js:
我有一个简单的路线定义express.js：
exports.save = function (request, response)
{
var file = request.body.file;
var content = request.body.content;
var saved = false;
if (fs.existsSync( file ))
{
saved = fs.writeFileSync(file, content, 'utf8');
}
console.log( saved ); // undefined or false, never true
response.send(saved ? 200 : 500, saved ? 'saved' : 'error'); // 500, error
};
Is if (typeof saved === 'undefined') saved = true;the only option? Feels hacky.
是if (typeof saved === 'undefined') saved = true;唯一的选择吗？感觉很鸡肋。
回答by fardjad
According to node.js source-codefs.writeFileSyncdoesn't return anything.
根据 node.js源代码fs.writeFileSync不返回任何内容。
It throws an Errorobject if something goes wrong. So you should write fs.writeFileSync(file, content, 'utf8');within a try-catchblock.
Error如果出现问题，它会抛出一个对象。所以你应该写fs.writeFileSync(file, content, 'utf8');在一个try-catch块内。
回答by Shuping
fs.writeFileSync does not return any value, if there is no exception happens that means the save succeeded; otherwise failed.
fs.writeFileSync 不返回任何值，如果没有异常发生说明保存成功；否则失败。
you may want to try the async version of file read
您可能想尝试文件读取的异步版本
fs.exists(file, function (exists) {
if (exists) {
fs.writeFiles(file, content, 'utf-8', function (err) {
if (err) {
response.send("failed to save");
} else {
response.send("succeeded in saving");
}
} else {
console.log('file does not exists');
}
}
