在此页

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

find() method returns a value in the typed array, if an element satisfies the provided testing function. Otherwise undefined 被返回。 TypedArray is one of the typed array types here.

另请参阅 findIndex() method, which returns the index of a found element in the typed array instead of its value.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

句法

typedarray.find(callback[, thisArg])
					

参数

callback

Function to execute on each value in the typed array, taking three arguments:

element

The current element being processed in the typed array.

index

The index of the current element being processed in the typed array.

array

The array find was called upon.

thisArg

Optional. Object to use as this when executing callback .

返回值

A value in the array if an element passes the test; otherwise, undefined .

描述

find method executes the callback function once for each element present in the typed array until it finds one where callback returns a true value. If such an element is found, find immediately returns the value of that element. Otherwise, find 返回 undefined . callback is invoked only for indexes of the typed array which have assigned values; it is not invoked for indexes which have been deleted or which have never been assigned values.

callback is invoked with three arguments: the value of the element, the index of the element, and the typed array object being traversed.

若 thisArg parameter is provided to find , it will be used as the this for each invocation of the callback . If it is not provided, then undefined 被使用。

find does not mutate the typed array on which it is called.

The range of elements processed by find is set before the first invocation of callback . Elements that are appended to the typed array after the call to find begins will not be visited by callback . If an existing, unvisited element of the typed array is changed by callback , its value passed to the visiting callback will be the value at the time that find visits that element's index; elements that are deleted are not visited.

范例

Find a prime number in a typed array

The following example finds an element in the typed array that is a prime number (or returns undefined if there is no prime number).

function isPrime(element, index, array) {
  var start = 2;
  while (start <= Math.sqrt(element)) {
    if (element % start++ < 1) {
      return false;
    }
  }
  return element > 1;
}
var uint8 = new Uint8Array([4, 5, 8, 12]);
console.log(uint8.find(isPrime)); // 5
								

规范

规范
ECMAScript (ECMA-262) The definition of '%TypedArray%.prototype.find' in that specification.

浏览器兼容性

The compatibility table on 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
find	Chrome 45	Edge 14	Firefox 37	IE No	Opera 32	Safari No	WebView Android 45	Chrome Android 45	Firefox Android 37	Opera Android 32	Safari iOS No	Samsung Internet Android 5.0	nodejs 4.0.0

图例

完整支持

完整支持

不支持

不支持

另请参阅

• TypedArray.prototype.findIndex()
• TypedArray.prototype.every()

元数据

• 最后修改： 2020 年 1 月 22 日

相关话题

1. 标准内置对象
2. TypedArray
3. 特性
   1. TypedArray.BYTES_PER_ELEMENT
   2. TypedArray.name
   3. TypedArray.prototype.buffer
   4. TypedArray.prototype.byteLength
   5. TypedArray.prototype.byteOffset
   6. TypedArray.prototype.length
   7. get TypedArray[@@species]
4. 方法
   1. TypedArray.from()
   2. TypedArray.of()
   3. TypedArray.prototype.copyWithin()
   4. TypedArray.prototype.entries()
   5. TypedArray.prototype.every()
   6. TypedArray.prototype.fill()
   7. TypedArray.prototype.filter()
   8. TypedArray.prototype.find()
   9. TypedArray.prototype.findIndex()
   10. TypedArray.prototype.forEach()
   11. TypedArray.prototype.includes()
   12. TypedArray.prototype.indexOf()
   13. TypedArray.prototype.join()
   14. TypedArray.prototype.keys()
   15. TypedArray.prototype.lastIndexOf()
   16. TypedArray.prototype.map()
   17. TypedArray.prototype.reduce()
   18. TypedArray.prototype.reduceRight()
   19. TypedArray.prototype.reverse()
   20. TypedArray.prototype.set()
   21. TypedArray.prototype.slice()
   22. TypedArray.prototype.some()
   23. TypedArray.prototype.sort()
   24. TypedArray.prototype.subarray()
   25. TypedArray.prototype.toLocaleString()
   26. TypedArray.prototype.toString()
   27. TypedArray.prototype.values()
   28. TypedArray.prototype[@@iterator]()
5. 相关页面：
6. Int8Array
7. Uint8Array
8. Uint8ClampedArray
9. Int16Array
10. Uint16Array
11. Int32Array
12. Uint32Array
13. Float32Array
14. Float64Array
15. BigInt64Array
16. BigUint64Array
17. 继承：
18. Function
19. 特性
    1. Function.arguments
    2. Function.caller
    3. Function.displayName
    4. Function.length
    5. Function.name
20. 方法
    1. Function.prototype.apply()
    2. Function.prototype.bind()
    3. Function.prototype.call()
    4. Function.prototype.toSource()
    5. Function.prototype.toString()
21. Object
22. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
23. 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()