JavaScript / ECMAScript

.env File Key-Value Line in JS

Parse KEY=value lines from .env config files, handling quoted values and trailing comments.

Try it in the JS tester →

Pattern

regexJS
^([A-Z_][A-Z0-9_]*)\s*=\s*(?:"([^"]*)"|'([^']*)'|([^#\s]*))(?:\s*#.*)?$   (flags: m)

JavaScript / ECMAScript code

jsJavaScript
const re = new RegExp("^([A-Z_][A-Z0-9_]*)\\s*=\\s*(?:\"([^\"]*)\"|'([^']*)'|([^#\\s]*))(?:\\s*#.*)?$", "m");
const input = "DATABASE_URL=postgres://localhost/db";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

Uses `String.prototype.matchAll` for global iteration (Node 12+ / all modern browsers).

How the pattern works

([A-Z_][A-Z0-9_]*) captures the variable name (uppercase + underscores by convention). The value alternation supports double-quoted, single-quoted, and unquoted values. (?:\s*#.*)? allows an optional inline comment. The m flag lets ^ and $ match individual lines in a multi-line file.

Examples

Input

DATABASE_URL=postgres://localhost/db

Matches

  • DATABASE_URL=postgres://localhost/db

Input

API_KEY="sk_live_abc123" # production

Matches

  • API_KEY="sk_live_abc123" # production

Input

lowercase=bad

No match

—

Same pattern, other engines

Python (re)

Supported

See how this pattern looks (and behaves) in Python's stdlib `re` module.

Go (RE2)

Supported

See how this pattern looks (and behaves) in Go's `regexp` package (RE2 engine).

← Back to .env File Key-Value Line overview (all engines)