在此页

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

reduce() method applies a function against an accumulator and each value of the typed array (from left-to-right) has to reduce it to a single value. This method has the same algorithm as Array.prototype.reduce() . TypedArray is one of the typed array types here.

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.reduce(callback[, initialValue])
					

参数

callback

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

previousValue

The value previously returned in the last invocation of the callback, or initialValue , if supplied (see below).

currentValue

The current element being processed in the typed array.

index

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

array

The typed array reduce was called upon.

initialValue

Optional. Object to use as the first argument to the first call of the callback .

返回值

The value that results from the reduction.

描述

reduce method executes the callback function once for each element present in the typed array, excluding holes in the typed array, receiving four arguments: the initial value (or value from the previous callback call), the value of the current element, the current index, and the typed array over which iteration is occurring.

The first time the callback is called, previousValue and currentValue can be one of two values. If initialValue is provided in the call to reduce , then previousValue will be equal to initialValue and currentValue will be equal to the first value in the typed array. If no initialValue was provided, then previousValue will be equal to the first value in the typed array and currentValue will be equal to the second.

If the typed array is empty and no initialValue was provided, TypeError would be thrown. If the typed array has only one element (regardless of position) and no initialValue was provided, or if initialValue is provided but the typed array is empty, the solo value would be returned without calling callback .

Polyfill

This method uses the same algorithm as Array.prototype.reduce() , so the same polyfill can be used here: simply replace Array.prototype.reduce with TypedArray.prototype.reduce .

范例

Sum up all values within an array

var total = new Uint8Array([0, 1, 2, 3]).reduce(function(a, b) {
  return a + b;
});
// total == 6
								

规范

规范
ECMAScript (ECMA-262) The definition of '%TypedArray%.prototype.reduce' 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
reduce	Chrome 45	Edge 14	Firefox 37	IE No	Opera 32	Safari 10	WebView Android 45	Chrome Android 45	Firefox Android 37	Opera Android No	Safari iOS 10	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.reduceRight()
• Array.prototype.reduce()

元数据

• 最后修改： May 20, 2020

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()