Parsing and serializing INI

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INI is a plain text configuration format built from key value pairs that can be grouped into sections. Many tools still read and write it, from git config to legacy application settings. The Standard Library provides parse and stringify functions for it in jsr:@std/ini.

import { parse, stringify } from "jsr:@std/ini";

An INI document is a list of key=value lines. A name in square brackets starts a section and the lines below it belong to that section.

const text = `
theme=dark
port=8080

[server]
host=localhost
debug=true
`;

To parse, pass the text to the parse function. Top level keys become properties and each section becomes a nested object.

const config = parse(text);
console.log(config.theme); // dark
console.log(config.server); // { host: "localhost", debug: "true" }

INI has no type system, so every value comes back as a string. The port looks like a number in the file but it is not one here.

console.log(typeof config.port); // string

To get typed values, pass a reviver function. It runs for every entry and receives the key, the raw value and the section name, and whatever it returns ends up in the result.

const typed = parse(text, {
  reviver(_key, value, _section) {
    if (value === "true") return true;
    if (value === "false") return false;
    const num = Number(value);
    return Number.isNaN(num) ? value : num;
  },
});
console.log(typed.port); // 8080
console.log(typed.server); // { host: "localhost", debug: true }

To serialize, pass an object to the stringify function. Nested objects turn back into sections, and numbers and booleans are written as their plain text form.

const ini = stringify({
  theme: "dark",
  port: 8080,
  server: { host: "localhost", debug: true },
});
console.log(ini);
// theme=dark
// port=8080
// [server]
// host=localhost
// debug=true

Run this example locally using the Deno CLI:

deno run https://docs.deno.com/examples/scripts/parsing_serializing_ini.ts

Parsing and serializing INI

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