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• 句法
• 描述
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

[@@toPrimitive]() method converts a Date object to a primitive value.

句法

Date()[Symbol.toPrimitive](hint);

					

返回值

The primitive value of the given Date object. Depending on the argument, the method can return either a string or a number.

描述

[@@toPrimitive]() 方法在 Date object returns a primitive value, that is either of type number or of type string.

若 hint is "string" or "default" , [@@toPrimitive]() tries to call the toString method. If the toString property does not exist, it tries to call the valueOf method and if the valueOf does not exist either, [@@toPrimitive]() throws a TypeError .

若 hint is "number" , [@@toPrimitive]() first tries to call valueOf , and if that fails, it calls toString .

JavaScript calls the [@@toPrimitive]() method to convert an object to a primitive value. You rarely need to invoke the [@@toPrimitive]() method yourself; JavaScript automatically invokes it when encountering an object where a primitive value is expected.

范例

Returning date primitives

const testDate = new Date(1590757517834);
// "Date Fri May 29 2020 14:05:17 GMT+0100 (British Summer Time)"
testDate[Symbol.toPrimitive]('string');
// Returns "Date Fri May 29 2020 14:05:17 GMT+0100 (British Summer Time)"
testDate[Symbol.toPrimitive]('number');
// Returns "1590757517834"
testDate[Symbol.toPrimitive]('default');
// Returns "Date Fri May 29 2020 14:05:17 GMT+0100 (British Summer Time)"
					

规范

规范
ECMAScript (ECMA-262) The definition of 'Date.prototype.@@toPrimitive' in that specification.

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

更新 GitHub 上的兼容性数据

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
@@toPrimitive	Chrome 47	Edge 15	Firefox 44	IE No	Opera 34	Safari 10	WebView Android 47	Chrome Android 47	Firefox Android 44	Opera Android 34	Safari iOS 10	Samsung Internet Android 5.0	nodejs 6.0.0

图例

完整支持

完整支持

不支持

不支持

另请参阅

• Symbol.toPrimitive

元数据

• 最后修改： May 29, 2020

相关话题

1. 标准内置对象
2. Date
3. 方法
   1. Date.UTC()
   2. Date.now()
   3. Date.parse()
   4. Date.prototype.getDate()
   5. Date.prototype.getDay()
   6. Date.prototype.getFullYear()
   7. Date.prototype.getHours()
   8. Date.prototype.getMilliseconds()
   9. Date.prototype.getMinutes()
   10. Date.prototype.getMonth()
   11. Date.prototype.getSeconds()
   12. Date.prototype.getTime()
   13. Date.prototype.getTimezoneOffset()
   14. Date.prototype.getUTCDate()
   15. Date.prototype.getUTCDay()
   16. Date.prototype.getUTCFullYear()
   17. Date.prototype.getUTCHours()
   18. Date.prototype.getUTCMilliseconds()
   19. Date.prototype.getUTCMinutes()
   20. Date.prototype.getUTCMonth()
   21. Date.prototype.getUTCSeconds()
   22. Date.prototype.getYear()
   23. Date.prototype.setDate()
   24. Date.prototype.setFullYear()
   25. Date.prototype.setHours()
   26. Date.prototype.setMilliseconds()
   27. Date.prototype.setMinutes()
   28. Date.prototype.setMonth()
   29. Date.prototype.setSeconds()
   30. Date.prototype.setTime()
   31. Date.prototype.setUTCDate()
   32. Date.prototype.setUTCFullYear()
   33. Date.prototype.setUTCHours()
   34. Date.prototype.setUTCMilliseconds()
   35. Date.prototype.setUTCMinutes()
   36. Date.prototype.setUTCMonth()
   37. Date.prototype.setUTCSeconds()
   38. Date.prototype.setYear()
   39. Date.prototype.toDateString()
   40. Date.prototype.toGMTString()
   41. Date.prototype.toISOString()
   42. Date.prototype.toJSON()
   43. Date.prototype.toLocaleDateString()
   44. Date.prototype.toLocaleString()
   45. Date.prototype.toLocaleTimeString()
   46. Date.prototype.toSource()
   47. Date.prototype.toString()
   48. Date.prototype.toTimeString()
   49. Date.prototype.toUTCString()
   50. Date.prototype.valueOf()
   51. Date.prototype[@@toPrimitive]
4. 继承：
5. Function
6. 特性
   1. Function.arguments
   2. Function.caller
   3. Function.displayName
   4. Function.length
   5. Function.name
7. 方法
   1. Function.prototype.apply()
   2. Function.prototype.bind()
   3. Function.prototype.call()
   4. Function.prototype.toSource()
   5. Function.prototype.toString()
8. Object
9. 特性
   1. Object.prototype.__proto__
   2. Object.prototype.constructor
10. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()