JavaScript prev function
A JavaScript equivalent of PHP’s prev
function prev (arr) {
// http://kevin.vanzonneveld.net
// + original by: Brett Zamir (http://brett-zamir.me)
// % note 1: Uses global: php_js to store the array pointer
// * example 1: transport = ['foot', 'bike', 'car', 'plane'];
// * example 1: prev(transport);
// * returns 1: false
// BEGIN REDUNDANT
this.php_js = this.php_js || {};
this.php_js.pointers = this.php_js.pointers || [];
var indexOf = function (value) {
for (var i = 0, length = this.length; i < length; i++) {
if (this[i] === value) {
return i;
}
}
return -1;
};
// END REDUNDANT
var pointers = this.php_js.pointers;
if (!pointers.indexOf) {
pointers.indexOf = indexOf;
}
var arrpos = pointers.indexOf(arr);
var cursor = pointers[arrpos + 1];
if (pointers.indexOf(arr) === -1 || cursor === 0) {
return false;
}
if (Object.prototype.toString.call(arr) !== '[object Array]') {
var ct = 0;
for (var k in arr) {
if (ct === cursor - 1) {
pointers[arrpos + 1] -= 1;
return arr[k];
}
ct++;
}
// Shouldn't reach here
}
if (arr.length === 0) {
return false;
}
pointers[arrpos + 1] -= 1;
return arr[pointers[arrpos + 1]];
}
Example 1
transport = ['foot', 'bike', 'car', 'plane'];
prev(transport);
Should return
false
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