Skip to main content

JS References

bigint​

  • Chrome 67+, Safari 14.1+, Node 10.4+
  • 能表示 int64
  • ⚠️ 不能和 number 直接运算
  • clamp/截断
    • BigInt.asIntN
    • BigInt.asUintN

Function​

// 检测 AsyncIterator/Generator
// next, return, throw
console.assert('next' in async function* () {}.prototype);
console.assert('next' in function* () {}.prototype);

(function* () {})[Symbol.toStringTag]; // GeneratorFunction
(async function* () {})[Symbol.toStringTag]; // AsyncGeneratorFunction
(async () => {})[Symbol.toStringTag]; // AsyncFunction

Symbol​

SymbolDescriptionUsed bySince
Symbol.asyncIterator返回对象默认的异步迭代器的方法for await...ofChrome 63+, Safari 12+, Node 10+
Symbol.hasInstance判断对象是否为某构造函数实例的方法instanceofChrome 50+, Safari 10+, Node 6+
Symbol.isConcatSpreadable指示对象是否可展开为数组元素的布尔值Array.prototype.concat()Chrome 38+, Safari 9+, Node 0.12+
Symbol.iterator返回对象默认迭代器的方法for...ofChrome 38+, Safari 9+, Node 0.12+
Symbol.match匹配字符串的方法String.prototype.match()Chrome 50+, Safari 10+, Node 6+
Symbol.matchAll返回所有匹配结果的迭代器的方法String.prototype.matchAll()Chrome 73+, Safari 13+, Node 12+
Symbol.replace替换字符串中匹配子串的方法String.prototype.replace()Chrome 50+, Safari 10+, Node 6+
Symbol.search返回字符串中匹配索引的方法String.prototype.search()Chrome 50+, Safari 10+, Node 6+
Symbol.species用于创建派生对象的构造函数-Chrome 51+, Safari 10+, Node 6.5+
Symbol.split拆分字符串的方法String.prototype.split()Chrome 50+, Safari 10+, Node 6+
Symbol.toPrimitive将对象转换为原始值的方法-Chrome 44+, Safari 9+, Node 0.12+
Symbol.toStringTag用于修改对象的默认描述字符串Object.prototype.toString()Chrome 43+, Safari 9+, Node 0.12+
Symbol.unscopables定义对象属性在 with 环境中不可见-Chrome 38+, Safari 9+, Node 0.12+

Symbol.toStringTag​

  • Object.prototype.toString()
  • [object ${@@toStringTag}]