How to copy contents from one buffer to another buffer in Node.js?
Published September 30, 2020
To copy contents from one
Buffer instance to another, we can use the
copy() method in the
Buffer instance in Node.js.
Let's say we have 2
Buffer instances from strings
Hai John and
Hello Roy like this,
// Buffer 1 const strBuff1 = Buffer.from("Hai John"); // Buffer 2 const strBuff2 = Buffer.from("Hello Roy");
We need to copy the
Roy part from the
strBuff2 instance to the
strBuff1 instance and paste it from the first position of the
Let's look at how it is done using the
copy() in the
// Buffer 1 const strBuff1 = Buffer.from("Hai John"); // Buffer 2 const strBuff2 = Buffer.from("Hello Roy"); // copy the Roy part from strBuff2 strBuff2.copy(strBuff1, 0, 6, 9); // display the contents in strBuff1 console.log(strBuff1.toString());
The above line reads like this: " Copy the contents from the byte 6 till byte 9 in the strBuff2 instance and paste it into the byte 0 of strBuff1 ".
- Accepts a valid
Bufferinstance to copy to (i.e
strBuff1) as the first argument.
- Accepts a starting point in the target buffer (i.e
strBuff1) to start pasting the content as the second argument.
- Accepts a starting point in the source buffer (i.e
strBuff2) to copy from as the third argument.
- Accepts an ending point in the source buffer (i.e
strBuff2) as the fourth argument.
See this example live in repl.it.