TypedArray.prototype.forEach()
The forEach()
method executes a provided function once
per array element. This method has the same algorithm as
Array.prototype.forEach()
. TypedArray is one of the
typed array types here.
Try it
Syntax
// Arrow function
forEach((element) => { /* ... */ } )
forEach((element, index) => { /* ... */ } )
forEach((element, index, array) => { /* ... */ } )
// Callback function
forEach(callbackFn)
forEach(callbackFn, thisArg)
// Inline callback function
forEach(function(element) { /* ... */ })
forEach(function(element, index) { /* ... */ })
forEach(function(element, index, array){ /* ... */ })
forEach(function(element, index, array) { /* ... */ }, thisArg)
Parameters
callbackFn
-
Function that produces an element of the new typed array.
The function is called with the following arguments:
element
-
The current element being processed in the typed array.
index
-
The index of the current element being processed in the array.
array
-
The array
forEach()
was called upon.
thisArg
Optional-
Value to use as
this
when executingcallbackFn
.
Return value
Description
The forEach()
method executes the provided
callbackFn
once for each element present in the typed array in
ascending order. It is not invoked for indexes that have been deleted or elided.
However, it is executed for elements that are present and have the value
undefined
.
callbackFn
is invoked with three arguments:
- the element value
- the element index
- the typed array being traversed
If a thisArg
parameter is provided to forEach()
,
it will be passed to callbackFn
when invoked, for use as its
this
value. Otherwise, the value undefined
will be passed
for use as its this
value. The this
value ultimately
observable by callbackFn
is determined according to
the usual rules for determining the this
seen by a function.
The range of elements processed by forEach()
is set before the first
invocation of callbackFn
. Elements that are appended to the typed array after
the call to forEach()
begins will not be visited by
callbackFn
. If the values of existing elements of the typed array
are changed, the value passed to callbackFn
will be the value at
the time forEach()
visits them; elements that are deleted before being
visited are not visited.
forEach()
executes the callbackFn
function once for each typed
array element; unlike every()
and
some()
it, always returns the value
undefined
.
Examples
Logging the contents of a typed array
The following code logs a line for each element in a typed array:
function logArrayElements(element, index, array) {
console.log(`a[${index}] = ${element}`);
}
new Uint8Array([0, 1, 2, 3]).forEach(logArrayElements);
// Logs:
// a[0] = 0
// a[1] = 1
// a[2] = 2
// a[3] = 3
Specifications
Specification |
---|
ECMAScript Language Specification # sec-%typedarray%.prototype.foreach |
Browser compatibility
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