arrayFilter

Used to filter an array to items for which the closure function returns true.

arrayFilter(array, function(item [,index, array]){} [, parallel] [, maxThreads]) → returns array

Member Function Syntax

someArray.filter(function(item [,index, array]){} [, parallel] [, maxThreads])

Argument Reference

array array
Required

callback boolean
Required

Closure or a function reference that will be called for each of the iteration. Returns true if the array element should be included in the filtered array. Support for passing the original array to the closure function added in CF11 Update 5.

Callback parameters:

value* any : The value for the current iteration
index* numeric : The current index for the iteration
array* array : A reference of the original array

parallel boolean
Default: `false`

Lucee 4.5+ true if the items can be executed in parallel

Values:

true
false

maxThreads numeric
Default: `20`

Lucee 4.5+ the maximum number of threads to use when parallel = true

Links more information about arrayFilter

Map, Reduce and other Higher Order Functions - A Primer for map, reduce, filter, and Higher Order Functions in general.
ColdFusion 11: .map() and .reduce() - A look at the new .map() and .reduce() methods that each of array, struct and lists all have

Examples
Sample code invoking the arrayFilter function

Simple numeric comparison

Take an array of struct items and use arrayFilter to return ones of a rating 3 and higher.

fruitArray = [{'fruit'='apple', 'rating'=4}, {'fruit'='banana', 'rating'=1}, {'fruit'='orange', 'rating'=5}, {'fruit'='mango', 'rating'=2}, {'fruit'='kiwi', 'rating'=3}];

favoriteFruits = arrayFilter(fruitArray, function(item){
	return item.rating >= 3;
});
writedump(serializeJSON(favoriteFruits));

Expected Result: [{"fruit":"apple","rating":4},{"fruit":"orange","rating":5},{"fruit":"kiwi","rating":3}]

Using a member function

This is the same example as above, but using a member function on the array instead of a standalone function.

fruitArray = [{'fruit'='apple', 'rating'=4}, {'fruit'='banana', 'rating'=1}, {'fruit'='orange', 'rating'=5}, {'fruit'='mango', 'rating'=2}, {'fruit'='kiwi', 'rating'=3}];

favoriteFruits = fruitArray.filter(function(item){
	return item.rating >= 3;
});
writedump(serializeJSON(favoriteFruits));

Expected Result: [{"fruit":"apple","rating":4},{"fruit":"orange","rating":5},{"fruit":"kiwi","rating":3}]

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