JavaScript / ECMAScript

Octal Number Literal in JS

Match modern ECMAScript-style octal literals (`0o755`) — strict per ES6+ syntax.

Try it in the JS tester →

Pattern

regexJS
\b0[oO][0-7]+\b   (flags: g)

JavaScript / ECMAScript code

jsJavaScript
const re = new RegExp("\\b0[oO][0-7]+\\b", "g");
const input = "perms = 0o755; mask = 0o022";
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. 0[oO] requires the modern ES6 octal prefix (case-insensitive on the o). [0-7]+ matches one or more octal digits (0–7). \b prevents matching into adjacent letters. Note: the loose `0755` form (no o) is technically a legacy octal in some languages but is dangerous in JS strict mode — this pattern requires the explicit `0o` prefix.

Examples

Input

perms = 0o755; mask = 0o022

Matches

  • 0o755
  • 0o022

Input

fileMode := 0o644

Matches

  • 0o644

Input

no octal

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).

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