我正在嘗試使用 node.js cp 功能復制一個檔案夾及其所有內容，如下所示
fs.cp('D:\\Developer\\insomniac-beta\\template', dir_path, {recursive: true});
但是它向我拋出了這個錯誤
node:internal/validators:232
throw new ERR_INVALID_ARG_TYPE(name, 'Function', value);
^
TypeError [ERR_INVALID_ARG_TYPE]: The "cb" argument must be of type function. Received undefined
at makeCallback (node:fs:191:3)
at Object.cp (node:fs:2848:14)
at D:\Developer\igbot\generate_config.js:30:13
at FSReqCallback.oncomplete (node:fs:193:23) {
code: 'ERR_INVALID_ARG_TYPE'
}
這怎么可能 ？我沒有給 cb 打電話？
uj5u.com熱心網友回復：
你錯過了一個論點。如檔案中所述，fs.cp 是一個異步函式，它接收一個回呼函式。
uj5u.com熱心網友回復：
最后的爭論需要是一個回呼函式
fs.cp('D:\\Developer\\insomniac-beta\\template', dir_path, (err)=>{
// handle error
})
uj5u.com熱心網友回復：
看起來您正在使用 Promises API，但您沒有顯示如何匯入模塊。這是當前節點 LTS (v) 的示例16.x：
參考：
fsPromises.cp(src, dest[, options])
import {promises as fs} from 'fs';
// ...
await fs.cp(sourceDir, destDir, {recursive: true});
這是一個完整的、自包含的示例，它創建示例目錄結構、復制它、驗證副本并清理示例資料：
example.mjs：
import * as path from 'path';
import {constants as fsConstants, promises as fs} from 'fs';
import {fileURLToPath} from 'url';
import {ok as assert} from 'assert/strict';
// Create sample folder structure, return relative file paths
async function createSampleFiles (rootDir) {
const writeFileOpts = {encoding: 'utf8'};
const filePaths = [];
await fs.mkdir(rootDir, {recursive: true});
let fPath = 'hello.txt';
filePaths.push(fPath);
fPath = path.join(rootDir, fPath);
let text = 'hello world\n';
await fs.writeFile(fPath, text, writeFileOpts);
let dir = 'more';
await fs.mkdir(path.join(rootDir, dir), {recursive: true});
fPath = path.join(dir, 'wow.txt');
filePaths.push(fPath);
fPath = path.join(rootDir, fPath);
text = 'wow\n';
await fs.writeFile(fPath, text, writeFileOpts);
return filePaths;
}
async function fsEntryExists (filePath) {
try {
await fs.access(filePath, fsConstants.F_OK);
return true;
}
catch (ex) {
if (ex instanceof Error && ex.code === 'ENOENT') return false;
throw ex;
}
}
async function assertFSEntryExists (filePath) {
assert(await fsEntryExists(filePath), `FS entry not found for "${filePath}"`);
}
async function main () {
const moduleDir = path.dirname(fileURLToPath(import.meta.url));
const sourceDir = path.join(moduleDir, 'data');
const destDir = path.join(moduleDir, 'data-copy');
const relativePaths = await createSampleFiles(sourceDir);
await fs.cp(sourceDir, destDir, {recursive: true});
let exitCode = 0;
try {
const filePaths = relativePaths.map(fPath => path.join(destDir, fPath));
for (const fPath of filePaths) await assertFSEntryExists(fPath);
console.log('Copy successful');
}
catch {
console.error('Copy failed');
exitCode = 1;
}
finally {
// Cleanup
for (const dir of [sourceDir, destDir]) {
if (await fsEntryExists(dir)) await fs.rm(dir, {recursive: true});
}
process.exit(exitCode);
}
}
main();
$ node --version
v16.15.0
$ node example.mjs
Copy successful
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標籤：javascript 节点.js