Node.js Buffer.from()方法
原文:https://www.geeksforgeeks.org/node-js-buffer-from-method/
Buffer.from()方法用于创建包含指定字符串、数组或缓冲区的新缓冲区。
语法:
Buffer.from( object, encoding )
参数:该方法接受两个参数，如上所述，如下所述:
- Object: This parameter can hold strings, buffers, arrays or array buffers.
- Code: If the object is a string, it is used to specify its code. It is an optional parameter. Its default value is utf8.
例 1:
// Node.js program to demonstrate the
// Buffer.from() Method
// Returns a new buffer with
// copy of the given string
var buf1 = Buffer.from("hello");
// Display the buffer object
// of the given string
console.log(buf1);
// Convert the buffer to the
// string and displays it
console.log(buf1.toString());
输出:
<Buffer 68 65 6c 6c 6f>
hello
例 2:
// Node.js program to demonstrate the
// Buffer.from() Method
// Creates an arrayBuffer with
// length 10
var arbuff = new ArrayBuffer(8);
// Returns a new buffer with a
// specified memory range within
// the arrayBuffer
var buf = Buffer.from(arbuff, 0, 2);
// Displays the length
console.log(buf.length);
输出:
2
例 3:
// Node.js program to demonstrate the
// Buffer.from() Method
// Create a new buffer with
// copy of the given string
var buf1 = Buffer.from("John");
// Create another buffer with
// copy of given buffer
var buf2 = Buffer.from(buf1);
// Display the buffer object
console.log(buf2);
// Convert the buffer to
// string and displays it
console.log(buf2.toString());
输出:
<Buffer 4a 6f 68 6e>
John
注意:以上程序使用node index.js命令编译运行。
参考:T2【https://nodejs . org/API/buffer . html # buffer _ class _ method _ buffer _ from _ string _ encoding
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