NQL String

Escape values for safe embedding in NQL filters.

Usage

javascript

escapeNqlString('can\'t stop');
// => "'can\\'t stop'"

`title:~${escapeNqlString(searchTerm)}`

The return value includes the surrounding quotes, so interpolate it directly rather than adding your own.

Why this exists

NQL delimits string values with quotes, so any value reaching a filter unescaped can terminate the string literal early and break the parser — a URL with a trailing ', or a post title containing ", is enough to make a filter unparseable.

Two rules are easy to get wrong, which is why this is shared rather than reimplemented per app:

Both quote characters must be escaped, not just the delimiter. The lexer rejects a bare " inside a single-quoted string.
Backslashes must not be escaped. NQL's only escape sequences are \' and \" — there is no \\ — so a lone backslash is a literal character and doubling it would query a different value.

The value must be non-empty: NQL's string rule requires at least one character.

Develop

This is a monorepo package.

Follow the instructions for the top-level repo.

git clone this repo & cd into it as usual
Run pnpm to install top-level dependencies.

Test

pnpm lint run eslint
pnpm test run the unit tests and typecheck