How to compare two buffers in Node.js?

Published September 25, 2020

To compare 2 buffers in Node.js, we can use the compare() method in the buffer object.

Let's say we have a buffer object like this,

// buffer 1
const buff1 = Buffer.from("EFG");

and another buffer like this,

// buffer 1
const buff1 = Buffer.from("EFG");

// buffer 2
const buff2 = Buffer.from("HIJ");

Now let's use the compare() in the buff1 Buffer object to compare our buff2 Buffer object like this,

// buffer 1
const buff1 = Buffer.from("EFG");

// buffer 2
const buff2 = Buffer.from("HIJ");

// comparing 2 buffers
const value = buff1.compare(buff2);

console.log(value); // -1
  • The method will return -1 if it finds that the buffer object which is passed as a parameter into the compare() method is coming after the string EFG in the first buffer.
  • The method will return 0 if it is the same.
  • The method will return 1 if it finds that the buffer object which is passed as a parameter into the compare() method is coming before the string EFG in the first buffer.

Let's do another example to clearly understand it better

Let's make 2 buffers,

// buffer 1
const buff1 = Buffer.from("KLM");

// buffer 2
const buff2 = Buffer.from("ABC");

// comparing 2 buffers
const value = buff1.compare(buff2);

console.log(value); // 1

If you look closely here we have the two buffers and in the first buffer we have string KLM and the second string ABC, we know that the string ABC is coming before the string KLM, so the compare() method will return 1.

The method will return 0 if the string are same like this,

// buffer 1
const buff1 = Buffer.from("ABC");

// buffer 2
const buff2 = Buffer.from("ABC");

// comparing 2 buffers
const value = buff1.compare(buff2);

console.log(value); // 0

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