Instructions for using the fs.truncateSync method in node.js_node.js

Method description:

Synchronized version of truncate(), file content interception operation.

Grammar:

Copy code The code is as follows:

fs.truncateSync(path, len)

Since this method belongs to the fs module, the fs module needs to be introduced before use (var fs= require(“fs”) )

Receive parameters:

path File path

len truncates the length, retaining only the characters within the character length, and the excess will be cleared.

Example:

Copy code The code is as follows:

var fs = require('fs');
fs.truncateSync('126.txt', 3);

Source code:

Copy code The code is as follows:

fs.truncateSync = function(path, len) {
if (util.isNumber(path)) {
// legacy
Return fs.ftruncateSync(path, len);
}
if (util.isUndefined(len)) {
len = 0;
}
// allow error to be thrown, but still close fd.
var fd = fs.openSync(path, 'r ');
try {
var ret = fs.ftruncateSync(fd, len);
} finally {
fs.closeSync(fd);
}
Return ret;
};