lastIndexOf.js•1.02 kB
var _curry2 = require('./internal/_curry2');
var _isArray = require('./internal/_isArray');
var equals = require('./equals');
/**
* Returns the position of the last occurrence of an item in an array, or -1 if
* the item is not included in the array. `R.equals` is used to determine
* equality.
*
* @func
* @memberOf R
* @since v0.1.0
* @category List
* @sig a -> [a] -> Number
* @param {*} target The item to find.
* @param {Array} xs The array to search in.
* @return {Number} the index of the target, or -1 if the target is not found.
* @see R.indexOf
* @example
*
* R.lastIndexOf(3, [-1,3,3,0,1,2,3,4]); //=> 6
* R.lastIndexOf(10, [1,2,3,4]); //=> -1
*/
module.exports = _curry2(function lastIndexOf(target, xs) {
if (typeof xs.lastIndexOf === 'function' && !_isArray(xs)) {
return xs.lastIndexOf(target);
} else {
var idx = xs.length - 1;
while (idx >= 0) {
if (equals(xs[idx], target)) {
return idx;
}
idx -= 1;
}
return -1;
}
});