✨parse .ini file

JS ⟩ value ⟩ object ⟩ regex ⟩ example ⟩ parse .ini file

// using "ini" package from npm
const { parse: parseINI } = require("ini");
parseINI("x = 10\ny = 20"),    // { x: '10', y: '20' }
// ⭐ .ini file format
// ---------------------------
// 1. Blank lines and lines starting with semicolons are ignored.
// 2. Lines wrapped in [ and ] start a new section.
// 3. Lines containing an alphanumeric identifier followed by an = character 
//    add a setting to the current section.
// 4. Anything else is invalid.
function parseINI(string) {

    let result = {};                // object to hold the top-level fields
    let currentSection = result;    // current section

    // ----------------------------
    // patterns (without '/g' flag)
    // ----------------------------
    
    const setting = /^(?<key>\w+)=(?<value>.*)$/;
    //                ╰── key ──╯ ╰─ value ──╯  <---- named groups

    const section = /^\[(?<sectionName>.*)\]$/;
    //                  ╰─ section name ─╯ 

    const blankOrComment = /^\s*(;.*)?$/;

    // begin to parse
    string
        .split(/\r?\n/)                  // split into separate lines
        .forEach(line => {
            
            let match;

            // ignore blank line or comment
            if (blankOrComment.test(line)) return;
            
            // new setting to current section
            if (match = line.match(setting)) {
                const { key, value } = match.groups;    // named groups
                currentSection[key] = value;
                return;                  // return from closure (early exit)
            }
            
            // new section
            if (match = line.match(section)) {
                const { sectionName } = match.groups;    // named groups
                currentSection = result[sectionName] = {};
                return;
            } 
            
            // anything else is invalid.
            throw new Error("Line: '" + line + "' is not valid.");
        });

    return result;
}

💈範例：

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