this kind of random search is a lot of information. What is there to ask for advice?
introduce fs into fs . Json can directly use the string read JSON.parse . If it is not a standard JSON, it is nothing more than a string cutting function split or regular cutting and assembling

const fs = require('fs');

const path = 'd:/node/demo.txt';
const str = fs.readFileSync(path).toString();

console.log(str);
console.log(JSON.parse(str));

1. Node can read the contents of a file. You can refer to Node official document-File Operation
2. Formatting the file content as JSON, depends on the format of your data, how the key:value is divided, and how each key is divided. You can use regular matching to get

text-2-json