fsPromises.copyFile(src, dest[, mode])
src
<string> | <Buffer> | <URL> 要复制的源文件名dest
<string> | <Buffer> | <URL> 复制操作的目标文件名mode
<integer> 指定复制操作行为的可选修饰符。 可以创建由两个或多个值的按位或组成的掩码(例如fs.constants.COPYFILE_EXCL | fs.constants.COPYFILE_FICLONE
) 默认值:0
。fs.constants.COPYFILE_EXCL
: 如果dest
已经存在,则复制操作将失败。fs.constants.COPYFILE_FICLONE
: 复制操作将尝试创建写时复制引用链接。 如果平台不支持写时复制,则使用后备复制机制。fs.constants.COPYFILE_FICLONE_FORCE
: 复制操作将尝试创建写时复制引用链接。 如果平台不支持写时复制,则该操作将失败。
- 返回: <Promise> 成功时将使用
undefined
履行。
异步地将 src
复制到 dest
。
默认情况下,如果 dest
已经存在,则会被覆盖。
无法保证复制操作的原子性。 如果在打开目标文件进行写入后发生错误,则将尝试删除目标文件。
import { copyFile, constants } from 'node:fs/promises';
try {
await copyFile('source.txt', 'destination.txt');
console.log('source.txt was copied to destination.txt');
} catch {
console.error('The file could not be copied');
}
// 通过使用 COPYFILE_EXCL,如果 destination.txt 存在,则该操作将失败。
try {
await copyFile('source.txt', 'destination.txt', constants.COPYFILE_EXCL);
console.log('source.txt was copied to destination.txt');
} catch {
console.error('The file could not be copied');
}
src
<string> | <Buffer> | <URL> source filename to copydest
<string> | <Buffer> | <URL> destination filename of the copy operationmode
<integer> Optional modifiers that specify the behavior of the copy operation. It is possible to create a mask consisting of the bitwise OR of two or more values (e.g.fs.constants.COPYFILE_EXCL | fs.constants.COPYFILE_FICLONE
) Default:0
.fs.constants.COPYFILE_EXCL
: The copy operation will fail ifdest
already exists.fs.constants.COPYFILE_FICLONE
: The copy operation will attempt to create a copy-on-write reflink. If the platform does not support copy-on-write, then a fallback copy mechanism is used.fs.constants.COPYFILE_FICLONE_FORCE
: The copy operation will attempt to create a copy-on-write reflink. If the platform does not support copy-on-write, then the operation will fail.
- Returns: <Promise> Fulfills with
undefined
upon success.
Asynchronously copies src
to dest
. By default, dest
is overwritten if it
already exists.
No guarantees are made about the atomicity of the copy operation. If an error occurs after the destination file has been opened for writing, an attempt will be made to remove the destination.
import { copyFile, constants } from 'node:fs/promises';
try {
await copyFile('source.txt', 'destination.txt');
console.log('source.txt was copied to destination.txt');
} catch {
console.error('The file could not be copied');
}
// By using COPYFILE_EXCL, the operation will fail if destination.txt exists.
try {
await copyFile('source.txt', 'destination.txt', constants.COPYFILE_EXCL);
console.log('source.txt was copied to destination.txt');
} catch {
console.error('The file could not be copied');
}