The for (x in obj) { … } statement allows to iterate over elements in objects such as arrays or associative arrays.
for (obj of objs) { … }
#!/usr/bin/env js52
//
// Iterating over array
//
var a = ['foo', 'bar', 'baz']
for (i in a) {
print(i);
// 0
// 1
// 2
}
for (j in a) {
print(a[j])
// foo
// bar
// baz
}
//
// Iterating over keys in an associative array (hash / dict):
//
var d = {x: 'eggs', y: 'why'}
for (k in d) {
print('d[' + k + '] = ' + d[k])
// d[x] = eggs
// d[y] = why
}