braces.js

"use strict";

const fs = require("fs");

let buf = "";

for (let i = 0; i < 1024 * 1024; i++) {
  buf += Math.random() > 0.5 ? "{" : "}";
}

fs.writeFileSync("random_braces.txt", buf);

gistfile1.txt

ggreer@carbon:~/Desktop% ls -la random_braces.txt 
-rw-r--r--  1 ggreer  staff  1048576 Jan 26 21:42 random_braces.txt
ggreer@carbon:~/Desktop% gzip random_braces.txt 
ggreer@carbon:~/Desktop% ls -la random_braces.txt.gz 
-rw-r--r--  1 ggreer  staff  166809 Jan 26 21:42 random_braces.txt.gz
ggreer@carbon:~/Desktop%