TypedArray.prototype.find()
The find()
method returns a value of an element in the
typed array, if it satisfies the provided testing function. Otherwise
undefined
is returned. TypedArray is one of the
typed array types here.
See also the findIndex()
method, which returns
the index of a found element in the typed array instead of its value.
Try it
Syntax
find(callbackFn)
find(callbackFn, thisArg)
Parameters
callbackFn
-
A function to execute for each element in the typed array. It should return a truthy value to indicate a matching element has been found, and a falsy value otherwise. 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 typed array.
array
-
The array
find()
was called upon.
thisArg
Optional-
A value to use as
this
when executingcallbackFn
. See iterative methods.
Return value
A value in the array if an element passes the test; otherwise, undefined
.
Description
The find()
method executes the callbackFn
function
once for each element present in the typed array until it finds one where
callbackFn
returns a true value. If such an element is found,
find()
immediately returns the value of that element. Otherwise,
find()
returns undefined
. callbackFn
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.
callbackFn
is invoked with three arguments: the value of the
element, the index of the element, and the typed array object being traversed.
If a thisArg
parameter is provided to find()
, it
will be used as the this
for each invocation of the
callbackFn
. If it is not provided, then undefined
is
used.
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 callbackFn
. Elements that are appended to the typed
array after the call to find()
begins will not be visited by
callbackFn
. If an existing, unvisited element of the typed array
is changed by callbackFn
, its value passed to the visiting
callbackFn
will be the value at the time that find()
visits that element's index; elements that are deleted are not visited.
Examples
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) {
let start = 2;
while (start <= Math.sqrt(element)) {
if (element % start++ < 1) {
return false;
}
}
return element > 1;
}
const uint8 = new Uint8Array([4, 5, 8, 12]);
console.log(uint8.find(isPrime)); // 5
Specifications
Specification |
---|
ECMAScript Language Specification # sec-%typedarray%.prototype.find |
Browser compatibility
BCD tables only load in the browser