PowerShell Equivalents for JavaScript Array Functions

Built-in

map

input | %{ expression($_) }

forEach

input | %{ [void]expression($_) }

filter

input | ?{ expression($_) }

indexOf

input.indexOf(value)

Close to built-in

some

if (input | ?{ expression($_) }) { ... }

every

if (-not input | ?{ !expression($_) }) { ... }

lastIndexOf

[array]::lastIndexOf(input, value)

Write it yourself

reduce

function reduce($fn, $a, $init) { $s = $init; $a | %{ $s = &$fn $s $_; }; $s; }