All

All returns true if all the values in the slice pass the predicate truth test.
Short-circuits and stops traversing the slice if a false element is found.

package main

import (
	"fmt"
	u "github.com/rjNemo/underscore"
)

func main() {
	nums := []int{1, 3, 5, 7, 9}
	isOdd := func(n int) bool { return n%2 != 0 }
	fmt.Println(u.All(nums, isOdd)) // true
}