Python (re)

JavaScript Variable Declaration in PY

Match JavaScript / TypeScript variable declarations (`var`, `let`, `const`), capturing the keyword and identifier name.

Try it in the PY tester →

Pattern

regexPY
\b(var|let|const)\s+([a-zA-Z_$][\w$]*)\s*(?:=|;|$)   (flags: gm)

Python (re) code

pyPython
import re

pattern = re.compile(r"\b(var|let|const)\s+([a-zA-Z_$][\w$]*)\s*(?:=|;|$)", re.MULTILINE)
input_text = "const x = 1;\\nlet name = \"alice\";\\nvar count;"
for m in pattern.finditer(input_text):
    print(m.group(0))

Stdlib `re` module — no third-party dependency. Works on Python 3.6+.

How the pattern works

\b(var|let|const) captures the declaration keyword at a word boundary. \s+ requires whitespace. ([a-zA-Z_$][\w$]*) captures a valid JS identifier (starts with letter, underscore, or $). \s*(?:=|;|$) matches the assignment or terminator so we don't mis-match function parameters.

Examples

Input

const x = 1;\nlet name = "alice";\nvar count;

Matches

  • const x =
  • let name =
  • var count;

Input

const { a, b } = obj

Matches

  • const { a, b } =

Input

// no decl

No match

Same pattern, other engines

← Back to JavaScript Variable Declaration overview (all engines)