76 lines
2.0 KiB
JavaScript
76 lines
2.0 KiB
JavaScript
'use strict';
|
|
|
|
/** @type {import('./shams')} */
|
|
/* eslint complexity: [2, 18], max-statements: [2, 33] */
|
|
module.exports = function hasSymbols() {
|
|
if (
|
|
typeof Symbol !== 'function' ||
|
|
typeof Object.getOwnPropertySymbols !== 'function'
|
|
) {
|
|
return false;
|
|
}
|
|
if (typeof Symbol.iterator === 'symbol') {
|
|
return true;
|
|
}
|
|
|
|
/** @type {{ [k in symbol]?: unknown }} */
|
|
var obj = {};
|
|
var sym = Symbol('test');
|
|
var symObj = Object(sym);
|
|
if (typeof sym === 'string') {
|
|
return false;
|
|
}
|
|
|
|
if (Object.prototype.toString.call(sym) !== '[object Symbol]') {
|
|
return false;
|
|
}
|
|
if (Object.prototype.toString.call(symObj) !== '[object Symbol]') {
|
|
return false;
|
|
}
|
|
|
|
// temp disabled per https://github.com/ljharb/object.assign/issues/17
|
|
// if (sym instanceof Symbol) { return false; }
|
|
// temp disabled per https://github.com/WebReflection/get-own-property-symbols/issues/4
|
|
// if (!(symObj instanceof Symbol)) { return false; }
|
|
|
|
// if (typeof Symbol.prototype.toString !== 'function') { return false; }
|
|
// if (String(sym) !== Symbol.prototype.toString.call(sym)) { return false; }
|
|
|
|
var symVal = 42;
|
|
obj[sym] = symVal;
|
|
for (var _ in obj) {
|
|
return false;
|
|
} // eslint-disable-line no-restricted-syntax, no-unreachable-loop
|
|
if (typeof Object.keys === 'function' && Object.keys(obj).length !== 0) {
|
|
return false;
|
|
}
|
|
|
|
if (
|
|
typeof Object.getOwnPropertyNames === 'function' &&
|
|
Object.getOwnPropertyNames(obj).length !== 0
|
|
) {
|
|
return false;
|
|
}
|
|
|
|
var syms = Object.getOwnPropertySymbols(obj);
|
|
if (syms.length !== 1 || syms[0] !== sym) {
|
|
return false;
|
|
}
|
|
|
|
if (!Object.prototype.propertyIsEnumerable.call(obj, sym)) {
|
|
return false;
|
|
}
|
|
|
|
if (typeof Object.getOwnPropertyDescriptor === 'function') {
|
|
// eslint-disable-next-line no-extra-parens
|
|
var descriptor = /** @type {PropertyDescriptor} */ (
|
|
Object.getOwnPropertyDescriptor(obj, sym)
|
|
);
|
|
if (descriptor.value !== symVal || descriptor.enumerable !== true) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
};
|