Evaluating queries in JavaScript

compile turns a query into a plain function once; call it on as many rows as you like.

import { compile } from '@qnot/core';

const matches = compile(fields, query);
const result = users.filter(matches);

The row type defaults to RowOf<typeof fields>. Struct fields read nested objects (address.city reads row.address.city), and array groups iterate the row's array. To read rows of another shape, pass get:

const matches = compile<typeof fields, User>(fields, query, {
  get: (user, field) => (field === 'plan' ? user.subscription.plan : user[field as keyof User]),
});

matches(fields, query, row) compiles and tests a single row in one call.

Semantics

• Incomplete rules are skipped by default, as the export codecs do, so a half-built query still filters; incompleteRules: false makes them fail closed instead.
• Invalid rules match nothing by default (a present value of the wrong type, out of range, or on an unknown field), so an untrusted query can never widen; invalidRules: 'skip' leaves them out. An empty query matches everything.
• Text compares case-insensitively unless the field sets caseSensitive: true.
• Dates and date-times compare as instants; times compare as HH:mm[:ss] strings.
• Null and undefined fail every comparison except isNull and isEmpty; notIn and notBetween don't match missing values.
• isEmpty matches null, undefined, '' and empty arrays; isNull only null/undefined.
• Multi-value fields: hasAny, hasAll, hasNone, setEq, setNeq compare the row's array against the rule's list.
• Array groups quantify over the array: some, all (true for an empty array), none, or a count ({ count: 'gte', value: 3 }, or between).
• Functions run their evaluate; custom operators run theirs.

Switch cases

compileCases compiles an ordered list of conditions with results; the first match wins.

import { compileCases } from '@qnot/core';

const route = compileCases(fields, {
  cases: [
    { when: vipQuery, then: 'concierge' },
    { when: emeaQuery, then: 'emea-team' },
  ],
  otherwise: 'self-serve',
});

route(user); // { value: 'emea-team', index: 1 }

See Routing and switch cases.