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 strBuff1
object.
Let's look at how it is done using the copy()
in the strBuff2
object.
// 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 ".
The method:
- Accepts a valid
Buffer
instance to copy to (i.estrBuff1
) 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.