JavaScript / ECMAScript

JSON Boolean / Null Literal in JS

Match JSON `true`, `false`, and `null` literal values, with word boundaries to avoid partial matches.

Try it in the JS tester →

Pattern

regexJS
\b(true|false|null)\b   (flags: g)

JavaScript / ECMAScript code

jsJavaScript
const re = new RegExp("\\b(true|false|null)\\b", "g");
const input = "{\"active\": true, \"deleted\": false, \"deleted_at\": null}";
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

\b is a word boundary on both sides so we don't match inside `nullable` or `falsey`. (true|false|null) captures one of the three JSON literals. Useful for quick log scraping or schema-detection passes when full JSON parsing is overkill.

Examples

Input

{"active": true, "deleted": false, "deleted_at": null}

Matches

  • true
  • false
  • null

Input

active=true; expired=false

Matches

  • true
  • false

Input

no literals

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 JSON Boolean / Null Literal overview (all engines)