var call = require('../internals/function-call'); var isObject = require('../internals/is-object'); var isSymbol = require('../internals/is-symbol'); var getMethod = require('../internals/get-method'); var ordinaryToPrimitive = require('../internals/ordinary-to-primitive'); var wellKnownSymbol = require('../internals/well-known-symbol'); var $TypeError = TypeError; var TO_PRIMITIVE = wellKnownSymbol('toPrimitive'); // `ToPrimitive` abstract operation // https://tc39.es/ecma262/#sec-toprimitive module.exports = function (input, pref) { if (!isObject(input) || isSymbol(input)) return input; var exoticToPrim = getMethod(input, TO_PRIMITIVE); var result; if (exoticToPrim) { if (pref === undefined) pref = 'default'; result = call(exoticToPrim, input, pref); if (!isObject(result) || isSymbol(result)) return result; throw $TypeError("Can't convert object to primitive value"); } if (pref === undefined) pref = 'number'; return ordinaryToPrimitive(input, pref); };