//#region src/is-valid-csosn/is-valid-csosn.d.ts
/**
 * Validates if a CSOSN (Código de Situação da Operação no Simples Nacional) code is valid.
 *
 * Accepted codes are `101, 102, 103, 201, 202, 203, 300, 400, 500, 900`, the table the
 * consolidated Anexo III-A of Convênio SINIEF s/nº 1970 carries.
 *
 * A string is only read as a code when it is written as the bare 3 digits with optional
 * surrounding whitespace. A CSOSN has no printed grouping (the NF-e carries the origin digit in
 * its own `orig` field), so a separator inside it (`"1-01"`) is rejected, and so is anything
 * else (`"abc101"`) instead of having its digits picked out. A number is only read
 * as a code when it is a non-negative safe integer, since a sign, a decimal point or a rounded
 * magnitude would otherwise be read as a code the caller never wrote.
 *
 * No CSOSN code starts with a zero, the table runs from `101` to `900`, so nothing is ever
 * padded here: a number and the string of the same digits are read identically, and a value
 * narrower than 3 digits is not a code at all.
 *
 * @param {string|number} value - The CSOSN code to be validated, e.g. `"101"` or `101`.
 * @returns {boolean} True when the code is a known CSOSN code, false otherwise.
 *
 * @see Official: https://www.confaz.fazenda.gov.br/legislacao/ajustes/sinief/cvsn_70
 * Convênio SINIEF s/nº 1970, whose Anexo III-A carries the CSOSN table in force.
 * @see Official: https://www.confaz.fazenda.gov.br/legislacao/ajustes/2010/aj_003_10
 * Ajuste SINIEF 03/2010, which instituted the CSOSN table.
 *
 * @example
 * ```typescript
 * isValidCsosn("101"); // true
 * isValidCsosn(900); // true
 * isValidCsosn("999"); // false
 * isValidCsosn("abc101"); // false (not a documented form)
 * isValidCsosn(-101); // false (not a non-negative safe integer)
 * ```
 */
export declare const isValidCsosn: (value: string | number) => boolean;
//#endregion